WO2013150757A1 - Zoom lens for projection, and projection-type display device - Google Patents

Zoom lens for projection, and projection-type display device Download PDF

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Publication number
WO2013150757A1
WO2013150757A1 PCT/JP2013/002173 JP2013002173W WO2013150757A1 WO 2013150757 A1 WO2013150757 A1 WO 2013150757A1 JP 2013002173 W JP2013002173 W JP 2013002173W WO 2013150757 A1 WO2013150757 A1 WO 2013150757A1
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WO
WIPO (PCT)
Prior art keywords
lens
lens group
group
projection
projection zoom
Prior art date
Application number
PCT/JP2013/002173
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French (fr)
Japanese (ja)
Inventor
賢 天野
Original Assignee
富士フイルム株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 富士フイルム株式会社 filed Critical 富士フイルム株式会社
Priority to CN201390000361.5U priority Critical patent/CN204129321U/en
Priority to JP2014509048A priority patent/JP5727669B2/en
Publication of WO2013150757A1 publication Critical patent/WO2013150757A1/en
Priority to US14/501,086 priority patent/US9423599B2/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
    • G02B15/177—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a negative front lens or group of lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/009—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras having zoom function
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/04—Reversed telephoto objectives
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/16—Optical objectives specially designed for the purposes specified below for use in conjunction with image converters or intensifiers, or for use with projectors, e.g. objectives for projection TV
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/143—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only
    • G02B15/1435—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative
    • G02B15/143507—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative arranged -++
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/144—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having four groups only
    • G02B15/1445—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having four groups only the first group being negative
    • G02B15/144515—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having four groups only the first group being negative arranged -+++
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
    • G02B15/20—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having an additional movable lens or lens group for varying the objective focal length
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/74—Projection arrangements for image reproduction, e.g. using eidophor
    • H04N5/7416—Projection arrangements for image reproduction, e.g. using eidophor involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration

Definitions

  • the present invention relates to a zoom lens, and more particularly to a projection zoom lens applied to a projection display device.
  • the present invention also relates to a projection display device equipped with such a projection zoom lens.
  • a light valve that performs light modulation to convert a video signal or an image signal into an optical signal is used.
  • a transmissive liquid crystal display element is known.
  • a cross dichroic prism is usually used for color synthesis, and the reduction side of the projection zoom lens is made telecentric in order to improve the synthesis characteristics. .
  • DMD digital micromirror device
  • the zoom lens for projection is also required to be capable of zooming at a high zoom ratio.
  • Patent Document 1 As projection zoom lenses that can satisfy the above-described requirements to some extent, those described in Patent Document 1 and Patent Document 2 have been known.
  • the zoom lens for projection described in Patent Document 1 has not only a small zoom ratio of about 1.3 times, but also a poor power balance of the third group and a large curvature of field.
  • the projection zoom lens disclosed in Patent Document 2 has a large zoom ratio of about 1.6 times, but the cost is low because five lenses are used for the first lens unit having a large lens diameter. It is expensive.
  • the present invention has been made in view of the above circumstances, and provides a projection zoom lens that is small and inexpensive and that can favorably correct various aberrations while ensuring a high zoom ratio of about 1.5 times. With the goal.
  • Another object of the present invention is to provide a projection display device that includes the projection zoom lens as described above and can display a high-quality image with a high zoom ratio.
  • the projection zoom lens according to the present invention includes: In a projection zoom lens that performs zooming operation by moving the third to fourth lens groups as a moving group,
  • the most magnified lens group is composed of a moving group having negative refractive power
  • the most reducing lens group is composed of a moving group having a positive refractive power
  • the most magnified lens group substantially consists of two lenses
  • the most magnified lens group includes an aspherical lens having at least one aspherical surface and a biconcave lens in order from the magnified side. It is desirable to be configured.
  • substantially ... arranged and configured means an optical element other than a lens, such as a lens having substantially no power, a diaphragm, a cover glass, and the like other than the lenses listed therein.
  • a mechanism portion such as a lens flange, a lens barrel, an image sensor, a camera shake correction mechanism, or the like is included is also included.
  • the term “substantially” is also used below, but its meaning is the same as described above.
  • the surface shape of the lens and the sign of the refractive power are considered in the paraxial region when an aspheric surface is included.
  • the aspheric lens is made of a plastic material
  • the biconcave lens is made of a glass material.
  • the focal length of the entire system at the wide angle end is fw
  • the focal length of the lens unit on the most reduction side is fr
  • the lens group on the most reduction side includes a biconcave lens, a positive lens, and a negative lens having a concave surface facing the enlargement side in order from the enlargement side.
  • the projection zoom lens of the present invention is more specifically, A negative first lens group, a positive second lens group, and a positive third lens group are arranged in order from the magnification side, When zooming, the first lens group, the second lens group, and the third lens group move independently as a moving group, It is desirable that the first lens group move to the reduction side and the second lens group and the third lens group move to the enlargement side when zooming from the wide-angle end to the telephoto end.
  • the zoom lens for projection according to the present invention is more specifically, A negative first lens group, a positive second lens group, a positive third lens group, and a positive fourth lens group are arranged in sequence from the magnification side, When zooming, the first lens group, the second lens group, the third lens group, and the fourth lens group move independently as a moving group, When zooming from the wide-angle end to the telephoto end, the first lens group moves to the reduction side, and the second lens group, the third lens group, and the fourth lens group move to the enlargement side. May be.
  • each of the second lens group and the third lens group is configured by a single lens.
  • the focal length of the entire system at the wide-angle end is fw
  • the back focus (air conversion distance) of the entire system at the wide-angle end is Bfw.
  • the maximum effective luminous flux height on the lens surface on the most reduction side is smaller than the maximum image height on the reduction side.
  • the projection display device of the present invention includes the projection zoom lens according to the present invention described above in addition to the light source, the light valve, and the illumination optical unit that guides the light beam from the light source to the light valve.
  • the light beam from the light source is optically modulated by the light valve and projected onto a screen by the projection zoom lens.
  • the most enlarged lens group has a negative refractive power.
  • the first lens group G1 which is the most magnified lens group, is substantially composed of two lenses.
  • the most demagnifying lens group is composed of a moving group having a positive refractive power.
  • the zoom lens for projection can be formed at low cost by configuring the lens group on the most enlarged side having a large lens diameter with a small number of lenses of two.
  • the projection zoom lens of the present invention is as follows.
  • the conditional expression (1) since the conditional expression (1) is satisfied, it is possible to satisfactorily correct off-axis aberrations such as distortion caused by the reduction in the number of lenses, and further, on the reduction side. It is possible to improve the power balance of the lens group and correct the field curvature and the like.
  • the lens group on the most enlargement side is configured by arranging an aspherical lens having at least one aspherical surface and a biconcave lens in order from the enlargement side.
  • the following effects can be obtained. That is, by disposing an aspheric lens at the most magnified position of the most magnified lens group, it is possible to effectively correct off-axis aberrations, particularly distortion. Further, by arranging a negative biconcave lens at the reduction side position of this lens group, it is possible to give an appropriate negative power as a whole, and it is possible to effectively correct off-axis aberrations such as astigmatism. It becomes like this.
  • the aspheric lens is a plastic lens
  • the biconcave lens is a glass lens
  • the following effects can be obtained.
  • the aberration correction function can be assigned to the aspheric plastic lens, and the necessary power can be assigned to the glass lens, thereby making the lens system less susceptible to thermal changes while fully exhibiting the aberration correction function. It becomes possible to build. Further, forming one lens from a plastic material is advantageous in terms of productivity and cost.
  • the conditional expression (2) defines a condition for satisfactorily correcting the curvature of field (particularly the curvature of the sagittal image surface), and even if the value of fr / fw becomes 2.0 or less, Even if it becomes 50.0 or more, it becomes difficult to correct the curvature of field well.
  • the conditional expression (2) is satisfied, the above problems can be prevented and the field curvature can be corrected well.
  • the lens group on the most reduction side has a biconcave lens, a positive lens, and a negative lens with a concave surface directed toward the enlargement side in order from the enlargement side, the above is described. Further, the function and effect obtained by satisfying the conditional expression (2) can be made more remarkable, and further, the fluctuation of spherical aberration due to zooming can be suppressed to a small value.
  • the projection zoom lens according to the present invention has a negative first lens group, a positive second lens group, and a positive third lens group, which are substantially arranged in order from the enlargement side.
  • the first lens group, the second lens group, and the third lens group move independently as a moving group, and when zooming from the wide angle end to the telephoto end, the first lens group moves to the reduction side, and the first lens group
  • the two lens group and the third lens group are configured to move to the enlargement side, it is possible to ensure a high zoom ratio without increasing the size of the entire lens system.
  • a negative first lens group, a positive second lens group, a positive third lens group, and a positive fourth lens group are arranged in order from the magnification side.
  • the first lens group, the second lens group, the third lens group, and the fourth lens group move independently as a moving group, and when zooming from the wide-angle end to the telephoto end, Even when one lens group is moved to the reduction side and the second lens group, the third lens group, and the fourth lens group are moved to the enlargement side, the entire lens system is not enlarged. In addition, a high zoom ratio can be ensured.
  • the projection zoom lens according to the present invention has the four-group configuration as described above, the number of lenses can be reduced particularly when each of the second lens group and the third lens group is composed of one single lens. In particular, it is possible to obtain a higher cost reduction effect with a small amount.
  • conditional expression (3) when the value of Bfwf / fw is 1.0 or less, it is difficult to place an illumination optical system that is placed close to the normal projection zoom lens. However, if conditional expression (3) is satisfied, Such an inconvenience is prevented, and the arrangement of the illumination optical system is facilitated.
  • the zoom lens for projection according to the present invention in particular, when the maximum effective luminous flux height on the lens surface on the most reduction side is smaller than the maximum image height on the reduction side, a sufficient lens back can be secured and the most reduction can be achieved. It is also possible to reduce the lens diameter of the lens group on the side.
  • the projection display apparatus of the present invention can display a high-quality image with a high zoom ratio.
  • Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 1 of this invention Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 2 of this invention. Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 3 of this invention. Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 4 of this invention. Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 5 of this invention. Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 6 of this invention.
  • (A) to (L) are aberration diagrams of the projection zoom lens according to Example 1 described above.
  • (A) to (L) are aberration diagrams of the projection zoom lens according to Example 2 described above.
  • FIG. 1 is a schematic configuration diagram of a projection display device according to an embodiment of the present invention.
  • FIG. 1 is a cross-sectional view showing the movement position of each lens group at the wide-angle end and the telephoto end when the zooming lens for projection according to an embodiment of the present invention is operated for zooming.
  • FIG. 2 to 6 are also sectional views showing other configuration examples according to the embodiment of the present invention, and correspond to projection zoom lenses of Examples 2 to 6, which will be described later, respectively.
  • the moving direction of the lens group when changing from the wide-angle end to the telephoto end is schematically shown by arrows between the positions.
  • the projection zoom lenses of Examples 1 and 2 shown in FIGS. 1 and 2 each have a three-group configuration, whereas the projection zoom lenses of Examples 3 to 6 shown in FIGS. It is a group structure.
  • FIG. 1 an embodiment of a projection zoom lens having a three-group configuration will be described mainly using the configuration shown in FIG. 1 as an example.
  • the projection zoom lens of the present embodiment can be used as a projection lens that projects image information displayed on a light valve onto a screen, for example.
  • the left side of the drawing is the enlarged side
  • the right side is the reduced side
  • the parallel plate PP is also shown assuming that it is mounted on a projection display device. That is, the image display surface of the light valve is usually arranged on the reduction side surface of the parallel plate PP.
  • FIGS the other configurations shown in FIGS.
  • a light beam given image information on the image display surface of the light valve enters the projection zoom lens via the parallel plate PP.
  • the projection zoom lens projects and displays an image based on the image information on a screen (not shown) arranged in the left direction of the drawing.
  • the image display surface of the light valve may be arranged away from the reduction side surface of the parallel plate PP.
  • the light beam from the light source is separated into three primary colors by a color separation optical system, and three light valves are used for each primary color. May be arranged so that a full-color image can be displayed.
  • the projection zoom lens according to this embodiment includes a first lens group G1 disposed closest to the enlargement side, a second lens group G2 disposed closer to the reduction side than the first lens group G1, and disposed closest to the reduction side. Only the third lens group G3 is provided as a substantial lens group.
  • the first lens group G1 has a negative refractive power
  • the second lens group G2 and the third lens group G3 each have a positive refractive power.
  • the first lens group G1, the second lens group G2, and the third lens group G3 are configured to move independently during zooming.
  • the first lens group G1 includes two lenses (first lens L1 and second lens L2), and the second lens group G2 includes two lenses (third lens L3 and fourth lens). L4), and the third lens group G3 includes four lenses (fifth lens L5 to eighth lens L8).
  • the example shown in FIG. 2 is different from the example of FIG. 1 in that the third lens group G3 includes five lenses (fifth lens L5 to ninth lens L9) with respect to the number of lenses.
  • the projection zoom lens is configured to perform focusing by moving the first lens group G1.
  • the first lens group G1 which is the most magnified lens group, is substantially composed of two lenses.
  • the zoom lens for projection can be formed at low cost by configuring the lens group on the most enlarged side having a large lens diameter with a small number of lenses of two.
  • the values of the conditions defined by the conditional expression (1) are shown in Table 19 together with the values of the conditions defined by the conditional expressions (2) and (3) described later for each example. Are shown together.
  • Table 19 since the focal length fw of the entire system is shown as 1.00, the values of fm, fr and Bfw are values of fm / fw, fr / fw and Bfw / fw, respectively.
  • the power of the first lens group G1 becomes too weak, leading to an increase in the size of the lens system.
  • the value of fm / fw is ⁇ 1.0 or more, which is the upper limit value
  • the power of the first lens group G1 becomes too strong, and it becomes difficult to correct various aberrations such as distortion.
  • the first lens group G1 which is the lens group closest to the magnification side, in order from the magnification side, an aspherical lens (first lens L1) having at least one aspheric surface, and Since the biconcave lens (second lens L2) is arranged, the following effects can be obtained. That is, by disposing an aspheric lens at the most magnified position of the most magnified lens group, it is possible to effectively correct off-axis aberrations, particularly distortion. Further, by arranging a negative biconcave lens at the reduction side position of this lens group, it is possible to give an appropriate negative power as a whole, and it is possible to effectively correct off-axis aberrations such as astigmatism. It becomes like this.
  • the first lens L1 that is an aspherical lens is a plastic lens
  • the second lens L2 that is a biconcave lens is a glass lens.
  • the focal length of the entire system at the wide-angle end is fw
  • the focal length of the third lens group G3, which is the most reducing lens group is fr. Is satisfied.
  • This conditional expression (2) defines the conditions for satisfactorily correcting the curvature of field (particularly the curvature of the sagittal image plane), and even if the value of fr / fw is 2.0 or less, Even if it becomes 50.0 or more, it becomes difficult to correct the curvature of field well.
  • the conditional expression (2) is satisfied, the above problems can be prevented and the field curvature can be corrected well.
  • the third lens group G3, which is the most reducing lens group, is arranged in order from the enlargement side, a biconcave lens (fifth lens L5), a positive lens (sixth lens L6), A negative lens (seventh lens L7) having a concave surface on the enlargement side is provided.
  • the following conditional expression (3) is satisfied, where the focal length of the entire system at the wide-angle end is fw and the back focus (air conversion distance) of the entire system at the wide-angle end is Bfw. ing.
  • the lens surface on the most reduction side (the eighth lens L8 in the example of FIG. 1 and the ninth lens L9 in the example of FIG. 2).
  • the maximum effective luminous flux height on each reduction side lens surface is smaller than the maximum image height on the reduction side. Thereby, a sufficient lens back can be secured, and the lens diameter of the lens group on the most reduction side can be reduced.
  • the three lens groups G1, G2, and G3 each move independently as a moving group during zooming, and the first lens when zooming from the wide-angle end to the telephoto end.
  • the group G1 moves to the reduction side
  • the second lens group G2 and the third lens group G3 move to the enlargement side.
  • FIGS. 3 to 6 ⁇ Embodiment with a four-group configuration
  • FIGS. 3 to 6 an embodiment of the projection zoom lens having a four-group configuration shown in FIGS. 3 to 6 will be described mainly by taking the configuration of FIG. 3 as an example.
  • the application of the projection zoom lens of the present embodiment to the projection display device is basically the same as the case of applying the projection zoom lens having the three-group configuration described above. A duplicate description is omitted.
  • the projection zoom lens according to the present embodiment includes a first lens group G1 that is disposed closest to the enlargement side, a second lens group G2 that is disposed closer to the reduction side than the first lens group G1, and the second lens group G2. Only the third lens group G3 disposed on the reduction side and the fourth lens group G4 disposed on the most reduction side are provided as substantial lens groups.
  • the first lens group G1 has a negative refractive power
  • the second lens group G2, the third lens group G3, and the fourth lens group G4 each have a positive refractive power.
  • the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 are configured to move independently during zooming.
  • the first lens group G1 includes two lenses (first lens L1 and second lens L2), and the second lens group G2 includes one lens (third lens L3).
  • the third lens group G3 includes one lens (fourth lens L4).
  • the fourth lens group G4 includes four lenses (fifth lens L5 to eighth lens L8) in the example shown in FIG. 3, and five lenses (fifth lens L5 to ninth lens L8) in the example shown in FIG. Lens L9), and in the example shown in FIG. 5 and FIG. 6, it consists of six lenses (fifth lens L5 to tenth lens L10).
  • the projection zoom lens is configured to perform focusing by moving the first lens group G1.
  • the first lens group G1 which is the most magnified lens group, is substantially composed of two lenses.
  • the zoom lens for projection can be formed at low cost by configuring the lens group on the most enlarged side having a large lens diameter with a small number of lenses of two.
  • the first lens group G1 which is the lens group closest to the magnification side, in order from the magnification side, an aspherical lens (first lens L1) having at least one aspherical surface and Since the biconcave lens (second lens L2) is arranged, off-axis aberrations, particularly distortion aberrations are effectively corrected, and off-axis aberrations such as astigmatism are effectively corrected.
  • first lens L1 which is the lens group closest to the magnification side
  • second lens L2 Since the biconcave lens (second lens L2) is arranged, off-axis aberrations, particularly distortion aberrations are effectively corrected, and off-axis aberrations such as astigmatism are effectively corrected.
  • the first lens L1 that is an aspheric lens is a plastic lens
  • the second lens L2 that is a biconcave lens is a glass lens. It is possible to construct a lens system that is less susceptible to thermal changes while fully exhibiting the above. Further, forming one lens from a plastic material is advantageous in terms of productivity and cost.
  • the lens group on the most reduction side is the fourth lens group G4. If the focal length is fr and the focal length of the entire system at the wide angle end is fw, the above conditions are also satisfied. Equation (2) is satisfied (see Table 19). Therefore, also in the present embodiment, the field curvature can be favorably corrected for the same reason as in the above-described three-group configuration embodiment.
  • the fourth lens group G4 which is the lens group closest to the reduction side, is arranged in order from the enlargement side, a biconcave lens (fifth lens L5), a positive lens (sixth lens L6), A negative lens (seventh lens L7) having a concave surface on the enlargement side is provided.
  • the above-mentioned conditional expression (3) is satisfied, assuming that the focal length of the entire system at the wide-angle end is fw and the back focus (air conversion distance) of the entire system at the wide-angle end is Bfw. Has been. Thereby, the arrangement of the illumination optical system is facilitated.
  • the lens surface closest to the reduction side (the eighth lens L8 in the example of FIG. 3 and the ninth lens L9 in the example of FIG. 4).
  • the maximum effective luminous flux height on each reduction side lens surface of the tenth lens L10 is smaller than the maximum image height on the reduction side. Thereby, a sufficient lens back can be secured, and the lens diameter of the lens group on the most reduction side can be reduced.
  • the four lens groups G1, G2, G3, and G4 each move independently as a moving group, and when zooming from the wide-angle end to the telephoto end.
  • the first lens group G1 moves to the reduction side
  • the second lens group G2, the third lens group G3, and the fourth lens group G4 move to the enlargement side.
  • the projection zoom lens according to the present embodiment can keep the cost low.
  • FIG. 13 schematically shows a part of a projection display apparatus according to an embodiment of the present invention.
  • the projection display apparatus 100 includes a light source 101, an illumination optical system 102, a DMD 103 as a light valve, and a projection zoom lens 104 according to an embodiment of the present invention.
  • the light beam emitted from the light source 104 is selectively converted into each light of the three primary colors (R, G, B) in time series by a color wheel (not shown), and the illumination optical system 102.
  • the light quantity distribution in the cross section perpendicular to the optical axis of the light beam is made uniform, and the DMD 103 is irradiated.
  • modulation switching to the color light is performed according to the color switching of the incident light.
  • the light modulated by the DMD 103 enters the projection zoom lens 104.
  • the projection zoom lens 104 projects an optical image by light modulated by the DMD 103 onto the screen 105.
  • the projection display device of the present invention can be modified in various ways from that shown in FIG.
  • RGB colors may be modulated simultaneously by three DMDs corresponding to each color light.
  • a color separation / synthesis prism (not shown) is disposed between the projection zoom lens 104 and the DMD 103.
  • other light valves such as a transmissive liquid crystal display element and a reflective liquid crystal display element can be used.
  • the projection zoom lenses of Examples 1 and 2 described below have a three-group configuration
  • the projection zoom lenses of Examples 3 to 6 have a four-group configuration.
  • FIG. 1 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens according to the first embodiment. Since the detailed description of FIG. 1 is as described above, the redundant description is omitted here unless otherwise required.
  • the projection zoom lens of Example 1 includes, in order from the magnification side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens having a positive refractive power.
  • the lens group G3 is arranged.
  • the first lens group G1 includes a first lens L1 which is an aspherical lens whose both surfaces are aspherical and a second lens L2 which is a biconcave lens in order from the magnification side.
  • the second lens group G2 includes a third lens L3, which is a biconvex lens, and a fourth lens L4, which is also a biconvex lens, in order from the magnification side.
  • the third lens unit L3 includes, in order from the magnification side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a negative meniscus lens, and an eighth lens L8 that is a biconvex lens. It is arranged and configured.
  • the maximum image height on the reduction side is 0.555.
  • the maximum effective light beam height on the lens surface on the reduction side of the eighth lens L8 arranged on the most reduction side is 0.409, which is smaller than the maximum image height. Therefore, a sufficient lens back can be secured, and the lens diameter of the third lens group G3 arranged on the most reduction side can be reduced.
  • Table 1 shows basic lens data of the projection zoom lens of Example 1.
  • the parallel plate PP described above is also included.
  • the Ri column indicates the radius of curvature of the i-th surface
  • the Di column indicates the surface spacing on the optical axis Z between the i-th surface and the i + 1-th surface.
  • the d-line (wavelength 587.6 nm) of the j-th (j 1, 2, 3,.
  • the ⁇ dj column indicates the Abbe number of the j-th component with respect to the d-line.
  • the values of the radius of curvature R and the surface interval D in Table 1 are values normalized by setting the focal length of the entire system of the projection zoom lens at the wide angle end to 1.00. In Table 1, values rounded to a predetermined digit are shown. The sign of the radius of curvature is positive when the surface shape is convex on the enlargement side and negative when the surface shape is convex on the reduction side.
  • the distance between the first lens group G1 and the second lens group G2, the distance between the second lens group G2 and the third lens group G3, and the distance between the third lens group G3 and the parallel plate PP. are variable intervals that change at the time of zooming. In the columns corresponding to these intervals, D4, D8, and D16 are indicated by adding “D” to the front surface number of the interval.
  • the interval between the first lens group G1 and the second lens group G2, the second lens group G2 and the second 4 shows the distance between the third lens group G3, the distance between the third lens group G3 and the fourth lens group G4, and the distance between the fourth lens group G4 and the parallel plate PP.
  • the number following “D” varies depending on the number of components in each embodiment, but the surface number on the front side of the interval is assigned. The same is true for all tables.
  • Table 2 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end when the projection zoom lens of Example 1 is zoomed, and the values of the variable intervals D4, D8, and D16. These numerical values are also values in the case where the projection distance is 151.087 (the same standardized value) normalized by setting the focal length of the entire system at the wide angle end to 1.00. As shown here, in this embodiment, the zoom ratio is as high as 1.50 times.
  • Table 3 shows aspherical data of the projection zoom lens of Example 1.
  • E indicates that the subsequent numerical value is a “power exponent” with a base of 10
  • the numerical value represented by an exponential function with the base 10 is “ Indicates that the value before E ′′ is multiplied.
  • “1.0E-02” indicates “1.0 ⁇ 10 ⁇ 2 ”.
  • Table 3 described above is the same in Tables 6, 9, 12, 15 and 18 described later.
  • the aspheric coefficients for the surface numbers S1 and S2 are shown.
  • FIGS. 7A to 7D respectively show spherical aberration, astigmatism, distortion (distortion aberration), and lateral chromatic aberration (chromatic aberration of magnification) at the wide-angle end of the projection zoom lens of Example 1.
  • the figure is shown.
  • (E) to (H) of the same figure show respective aberration diagrams of spherical aberration, astigmatism, distortion, and lateral chromatic aberration at the intermediate focal position of the projection zoom lens of Example 1.
  • (I) to (L) in the same figure show aberration diagrams of spherical aberration, astigmatism, distortion, and lateral chromatic aberration at the telephoto end of the projection zoom lens of Example 1, respectively.
  • FIG. 7 shows the F number Fno. At the wide angle end, the intermediate focal position, and the telephoto end of the first embodiment. The total angle of view 2 ⁇ (in degrees) is also shown.
  • the aberration diagrams in FIGS. 7A to 7L are based on the d-line, but in the spherical aberration diagram, the F-line (wavelength wavelength 486.1 nm) and the C-line (wavelength 656.3 nm). Are also shown, and the chromatic aberration diagram for magnification shows aberrations for the F-line and C-line.
  • aberrations in the sagittal direction and the tangential direction are indicated by a solid line and a broken line, respectively.
  • Example 1 The symbols, meanings, and description methods of the lens group arrangement diagram, table, and aberration diagram of Example 1 described above are basically the same for the following Examples 2 to 6 unless otherwise specified.
  • the lens group arrangement diagram (FIG. 1) of Example 1 described above is at the wide-angle end and the telephoto end, and the aberration diagram is at the wide-angle end, the intermediate focal position, and the telephoto end. The same applies to 2-6.
  • FIG. 2 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens according to the second embodiment.
  • the projection zoom lens of Example 2 includes, in order from the magnification side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens having a positive refractive power.
  • the lens group G3 is arranged.
  • the first lens group G1 includes a first lens L1 that is an aspherical lens whose both surfaces are aspherical and a second lens L2 that is a biconcave lens in order from the magnification side.
  • the second lens group G2 includes a third lens L3, which is a biconvex lens, and a fourth lens L4, which is also a biconvex lens, in order from the magnification side.
  • the third lens group G3 includes, in order from the magnification side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a biconcave lens, an eighth lens L8 that is a positive meniscus lens, and A ninth lens L9, which is a biconvex lens, is arranged.
  • the maximum image height on the reduction side is 0.554.
  • the maximum effective light beam height on the reduction-side lens surface of the ninth lens L9 arranged on the most reduction side is 0.407, which is smaller than the maximum image height (note that these values are also at the wide-angle end). This is standardized with the focal length of the entire system as 1.00 (hereinafter the same). Therefore, a sufficient lens back can be secured, and the lens diameter of the third lens group G3 arranged on the most reduction side can be reduced.
  • Table 4 shows basic lens data of the projection zoom lens of Example 2.
  • Table 5 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end, and the values of the variable intervals D4, D8, and D18 when the projection zoom lens of Example 2 is zoomed. As shown here, in this embodiment, the zoom ratio is as high as 1.50 times. These numerical values are values when the projection distance is 151.073.
  • Table 6 shows aspherical data of the projection zoom lens of Example 2.
  • FIGS. 8A to 8L show aberration diagrams of the projection zoom lens of Example 2, respectively. Each aberration shown here is obtained when the projection distance is 151.073 described above.
  • FIG. 3 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens according to the third embodiment.
  • the projection zoom lens of Example 3 includes, in order from the enlargement side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a positive refractive power. G3 and a fourth lens group G4 having a positive refractive power are arranged.
  • the first lens group G1 includes a first lens L1 which is an aspherical lens whose both surfaces are aspherical and a second lens L2 which is a biconcave lens in order from the magnification side.
  • the second lens group G2 includes a third lens L3 that is a single biconvex lens.
  • the third lens group G3 is also composed of a fourth lens L4 which is a single biconvex lens.
  • the fourth lens group G4 includes, in order from the magnification side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a negative meniscus lens, and an eighth lens L8 that is a biconvex lens. Configured.
  • the maximum image height on the reduction side is 0.555.
  • the maximum effective luminous flux height on the lens surface on the reduction side of the eighth lens L8 arranged on the most reduction side is 0.414, which is smaller than the maximum image height. Therefore, a sufficient lens back can be secured, and the lens diameter of the fourth lens group G4 arranged on the most reduction side can be reduced.
  • Table 7 shows basic lens data of the projection zoom lens of Example 3.
  • Table 8 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end, and the values of the variable intervals D4, D6, D8, and D16 when the projection zoom lens of Example 3 is zoomed. .
  • the zoom ratio is as high as 1.50 times. These numerical values are values when the projection distance is 151.121.
  • Table 9 shows aspherical data of the projection zoom lens of Example 3.
  • FIGS. 9A to 9L show aberration diagrams of the projection zoom lens of Example 3, respectively. Each aberration shown here is obtained when the projection distance is 151.121 described above.
  • FIG. 4 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens of Example 4.
  • the projection zoom lens of Example 4 includes, in order from the magnification side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a positive refractive power. G3 and a fourth lens group G4 having a positive refractive power are arranged.
  • the first lens group G1 includes a first lens L1 which is an aspherical lens whose both surfaces are aspherical and a second lens L2 which is a biconcave lens in order from the magnification side.
  • the second lens group G2 includes a third lens L3 that is a single biconvex lens.
  • the third lens group G3 is also composed of a fourth lens L4 which is a single biconvex lens.
  • the fourth lens group G4 includes, in order from the magnifying side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a biconcave lens, an eighth lens L8 that is a positive meniscus lens, and both A ninth lens L9, which is a convex lens, is arranged.
  • the maximum image height on the reduction side is 0.554.
  • the maximum effective luminous flux height on the lens surface on the reduction side of the ninth lens L9 arranged on the most reduction side is 0.401, which is smaller than the maximum image height. Therefore, a sufficient lens back can be secured, and the lens diameter of the fourth lens group G4 arranged on the most reduction side can be reduced.
  • Table 10 shows basic lens data of the projection zoom lens of Example 4.
  • Table 11 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end, and the values of the variable intervals D4, D6, D8, and D18 when the zoom lens for projection of Example 4 is zoomed. .
  • the zoom ratio is as high as 1.50 times. These numerical values are values when the projection distance is 151.078.
  • Table 12 shows aspherical data of the projection zoom lens of Example 4.
  • FIGS. 10A to 10L show aberration diagrams of the projection zoom lens of Example 4, respectively. Each aberration shown here is obtained when the projection distance is 151.078 described above.
  • FIG. 5 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens according to the fifth embodiment.
  • the projection zoom lens of Example 5 includes, in order from the magnification side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a positive refractive power. G3 and a fourth lens group G4 having a positive refractive power are arranged.
  • the first lens group G1 includes a first lens L1 which is an aspherical lens whose both surfaces are aspherical and a second lens L2 which is a biconcave lens in order from the magnification side.
  • the second lens group G2 includes a third lens L3 that is a single biconvex lens.
  • the third lens group G3 is also composed of a fourth lens L4 which is a single biconvex lens.
  • the fourth lens group G4 includes, in order from the magnifying side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a biconcave lens, an eighth lens L8 that is a positive meniscus lens, and a biconvex lens. And a tenth lens L10 which is a biconvex lens.
  • the maximum image height on the reduction side is 0.553.
  • the maximum effective luminous flux height on the lens surface on the reduction side of the tenth lens L10 arranged on the most reduction side is 0.415, which is smaller than the maximum image height. Therefore, a sufficient lens back can be secured, and the lens diameter of the fourth lens group G4 arranged on the most reduction side can be reduced.
  • Table 13 shows basic lens data of the projection zoom lens of Example 5.
  • Table 14 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end, and the values of the variable intervals D4, D6, D8, and D20 when the zoom lens for projection of Example 5 is zoomed. .
  • the zoom ratio is as high as 1.50 times. These numerical values are values when the projection distance is 120.516.
  • Table 15 shows aspherical data of the projection zoom lens of Example 5.
  • FIGS. 11A to 11L show respective aberration diagrams of the projection zoom lens of Example 5.
  • FIG. Each aberration shown here is obtained when the projection distance is 120.516 described above.
  • FIG. 6 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens according to the sixth embodiment.
  • the projection zoom lens of Example 6 includes, in order from the magnification side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a positive refractive power. G3 and a fourth lens group G4 having a positive refractive power are arranged.
  • the first lens group G1 includes a first lens L1 which is an aspherical lens whose both surfaces are aspherical and a second lens L2 which is a biconcave lens in order from the magnification side.
  • the second lens group G2 includes a third lens L3 that is a single biconvex lens.
  • the third lens group G3 is also composed of a fourth lens L4 which is a single biconvex lens.
  • the fourth lens group G4 includes, in order from the magnifying side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a biconcave lens, an eighth lens L8 that is a positive meniscus lens, and a biconvex lens. And a tenth lens L10 which is a biconvex lens.
  • the maximum image height on the reduction side is 0.553.
  • the maximum effective light beam height on the lens surface on the reduction side of the tenth lens L10 arranged on the most reduction side is 0.408, which is smaller than the maximum image height. Therefore, a sufficient lens back can be secured, and the lens diameter of the fourth lens group G4 arranged on the most reduction side can be reduced.
  • Table 16 shows basic lens data of the projection zoom lens of Example 6.
  • Table 17 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end, and the values of the variable intervals D4, D6, D8, and D20 when the zoom lens for projection of Example 6 is zoomed. .
  • the zoom ratio is as high as 1.64 times. These numerical values are values when the projection distance is 120.472.
  • Table 18 shows aspherical data of the projection zoom lens of Example 6.
  • FIGS. 12A to 12L show aberration diagrams of the projection zoom lens of Example 6.
  • FIG. Each aberration shown here is obtained when the projection distance is 120.472 as described above.
  • Table 19 shows values of conditions defined by the conditional expressions (1) to (3) (that is, character expression portions). As described above, since the focal length fw of the entire system is shown as 1.00, the values of fm, fr and Bfw are values of fm / fw, fr / fw and Bfw / fw, respectively.
  • the projection zoom lens according to the present invention is not limited to the above examples, and various modifications can be made. It is possible to appropriately change the radius of curvature, the surface spacing, the refractive index, and the Abbe number.
  • the projection display device of the present invention is not limited to the above-described configuration.
  • the light valve used and the optical member used for light beam separation or light beam synthesis are not limited to the above-described configuration. Various modifications can be made.

Abstract

[Problem] To enable a reduction in size and costs for a zoom lens for projection, whilst also enabling excellent aberration correction. [Solution] A zoom lens for projection in which power variation is carried out by moving three to four lens groups as moving groups, wherein a first lens group (G1), which is the lens group that is furthest to the magnification side, comprises a moving group having negative refractive power, a third lens group (G3), which is the lens group that is furthest to the reduction side, comprises a moving group having positive refractive power, and the first lens group (G1), which is the lens group that is furthest to the magnification side, essentially comprises two lenses (L1 and L2). Furthermore, conditional expression (1) is satisfied, wherein fw is the focal length of the entire system at the wide-angle end and fm is the focal length of the lens group which is furthest to the magnification side:　-3.5<fm/fw<-1.0... (1)

Description

投写用ズームレンズおよび投写型表示装置Projection zoom lens and projection display device
　本発明はズームレンズに関し、特に、投写型表示装置に適用される投写用ズームレンズに関するものである。 The present invention relates to a zoom lens, and more particularly to a projection zoom lens applied to a projection display device.
　また本発明は、そのような投写用ズームレンズを備えた投写型表示装置に関するものである。 The present invention also relates to a projection display device equipped with such a projection zoom lens.
　近年、パソコンの普及等と相俟って投写型表示装置（プロジェクタ）の需要が高まっており、その市場は大きく拡大しつつある。 In recent years, the demand for projection display devices (projectors) has increased along with the spread of personal computers, and the market has been greatly expanding.
　投写型表示装置には、映像信号や画像信号を光信号に変える光変調を行うライトバルブが使用されるが、その一つとして透過型液晶表示素子が知られている。透過型液晶表示素子が適用される光学系においては、通常、色合成のためにクロスダイクロイックプリズムが用いられており、その合成特性を向上させるために投写用ズームレンズの縮小側がテレセントリックとされている。 In a projection display device, a light valve that performs light modulation to convert a video signal or an image signal into an optical signal is used. As one of them, a transmissive liquid crystal display element is known. In an optical system to which a transmissive liquid crystal display element is applied, a cross dichroic prism is usually used for color synthesis, and the reduction side of the projection zoom lens is made telecentric in order to improve the synthesis characteristics. .
　また、より高精細で、コントラスト比の大きい投影画像を得たいという要求の高まりから、近時、ライトバルブとしてＤＭＤ（デジタル・マイクロミラー・デバイス：登録商標）素子を搭載した投写型表示装置が注目されている。反射型ライトバルブであるＤＭＤ素子を用いる場合は、投写用ズームレンズの縮小側をテレセントリックにする必要がないことから、縮小側の瞳をパネルに近い位置に設定できるので、縮小側のレンズ部分を小型化することが可能になる。 Also, due to the increasing demand for higher definition and high contrast ratio projection images, projection display devices equipped with DMD (digital micromirror device: registered trademark) elements as light valves have recently attracted attention. Has been. When using a DMD element that is a reflection type light valve, the reduction side of the projection zoom lens does not need to be telecentric, so the reduction side pupil can be set at a position close to the panel. It becomes possible to reduce the size.
　他方、投写型表示装置の設置性の観点から、投写用ズームレンズには高いズーム比で変倍可能であることも求められる。 On the other hand, from the viewpoint of installability of the projection display device, the zoom lens for projection is also required to be capable of zooming at a high zoom ratio.
　上述したような要求をある程度満たし得る投写用ズームレンズとして、従来、特許文献１および特許文献２に記載されたものが公知となっている。 As projection zoom lenses that can satisfy the above-described requirements to some extent, those described in Patent Document 1 and Patent Document 2 have been known.
特開2004-77950号公報JP 2004-77950 A 特開2007-271697号公報JP 2007-271697
　しかし、特許文献１に記載された投写用ズームレンズは、ズーム比が１．３倍程度と小さいばかりか、第３群のパワーバランスが悪く、像面湾曲が大きいものとなっている。また特許文献２に示された投写用ズームレンズは、ズーム比が１．６倍程度と大きいものの、レンズ径の大きい第１群に５枚のレンズを使用していることもあって、コストが高いものとなっている。 However, the zoom lens for projection described in Patent Document 1 has not only a small zoom ratio of about 1.3 times, but also a poor power balance of the third group and a large curvature of field. The projection zoom lens disclosed in Patent Document 2 has a large zoom ratio of about 1.6 times, but the cost is low because five lenses are used for the first lens unit having a large lens diameter. It is expensive.
　本発明は上記の事情に鑑みてなされたものであり、１．５倍程度の高いズーム比を確保しながら、小型かつ安価で、しかも諸収差を良好に補正できる投写用ズームレンズを提供することを目的とする。 The present invention has been made in view of the above circumstances, and provides a projection zoom lens that is small and inexpensive and that can favorably correct various aberrations while ensuring a high zoom ratio of about 1.5 times. With the goal.
　また本発明は、上述のような投写用ズームレンズを備えて、高いズーム比で高画質の画像を表示できる投写型表示装置を提供することを目的とする。 Another object of the present invention is to provide a projection display device that includes the projection zoom lens as described above and can display a high-quality image with a high zoom ratio.
　本発明による投写用ズームレンズは、 
　移動群として３群ないし４群のレンズ群を移動させて変倍動作を行う投写用ズームレンズにおいて、
　最も拡大側のレンズ群は負の屈折力を有する移動群から構成され、
　最も縮小側のレンズ群は正の屈折力を有する移動群から構成され、
　前記最も拡大側のレンズ群は実質的に２枚のレンズからなり、
　広角端における全系の焦点距離をｆwとし、最も拡大側のレンズ群の焦点距離をｆmとして、下記条件式（１）
　　－３．５＜ fm／fw ＜－１．０・・・（１）
を満たすことを特徴とするものである。 The projection zoom lens according to the present invention includes:
In a projection zoom lens that performs zooming operation by moving the third to fourth lens groups as a moving group,
The most magnified lens group is composed of a moving group having negative refractive power,
The most reducing lens group is composed of a moving group having a positive refractive power,
The most magnified lens group substantially consists of two lenses,
When the focal length of the entire system at the wide-angle end is fw, and the focal length of the lens unit closest to the magnification is fm, the following conditional expression (1)
-3.5 <fm / fw <-1.0 (1)
It is characterized by satisfying.
　なお、上記構成を有する本発明の投写用ズームレンズにおいては、上記最も拡大側のレンズ群が実質的に、拡大側より順に、少なくとも１面が非球面である非球面レンズおよび、両凹レンズを配置して構成されていることが望ましい。 In the projection zoom lens of the present invention having the above-described configuration, the most magnified lens group includes an aspherical lens having at least one aspherical surface and a biconcave lens in order from the magnified side. It is desirable to be configured.
　ここで、上記の「実質的に・・・配置して構成され」とは、そこに挙げられたレンズ以外に、実質的にパワーを有さないレンズ、絞りやカバーガラス等レンズ以外の光学要素、レンズフランジ、レンズバレル、撮像素子、手振れ補正機構等の機構部分等を持つ場合も含むものとする。この「実質的に」との用語は以下でも用いられているが、その意味するところは全て上に述べたものと同じである。 Here, “substantially ... arranged and configured” means an optical element other than a lens, such as a lens having substantially no power, a diaphragm, a cover glass, and the like other than the lenses listed therein. In addition, a case where a mechanism portion such as a lens flange, a lens barrel, an image sensor, a camera shake correction mechanism, or the like is included is also included. The term “substantially” is also used below, but its meaning is the same as described above.
　なお、本発明の投写用ズームレンズにおけるレンズの面形状、屈折力の符号は、非球面が含まれているものについては近軸領域で考えるものとする。 In the projection zoom lens of the present invention, the surface shape of the lens and the sign of the refractive power are considered in the paraxial region when an aspheric surface is included.
　また、上記の非球面レンズはプラスチック材から形成され、上記の両凹レンズはガラス材から形成されていることが好ましい。 Also, it is preferable that the aspheric lens is made of a plastic material, and the biconcave lens is made of a glass material.
　また、本発明の投写用ズームレンズにおいては、広角端における全系の焦点距離をｆwとし、最も縮小側のレンズ群の焦点距離をｆrとして、下記条件式（２）
　　２．０＜ ｆr／ｆw ＜５０．０・・・（２）
が満たされていることが望ましい。 In the zoom lens for projection according to the present invention, the focal length of the entire system at the wide angle end is fw, and the focal length of the lens unit on the most reduction side is fr, and the following conditional expression (2)
2.0 <fr / fw <50.0 (2)
It is desirable that
　さらに本発明の投写用ズームレンズにおいては、前記最も縮小側のレンズ群が拡大側より順に、両凹レンズ、正レンズ、拡大側に凹面を向けた負レンズを有していることが望ましい。 Further, in the projection zoom lens according to the present invention, it is desirable that the lens group on the most reduction side includes a biconcave lens, a positive lens, and a negative lens having a concave surface facing the enlargement side in order from the enlargement side.
　また、本発明の投写用ズームレンズはより具体的に、
　拡大側より順に実質的に、負の第１レンズ群、正の第２レンズ群および正の第３レンズ群が配列されてなり、
　変倍に際し前記第１レンズ群、第２レンズ群および第３レンズ群が移動群として各々独立して移動し、
　広角端から望遠端まで変倍する際に前記第１レンズ群は縮小側に移動し、前記第２レンズ群および前記第３レンズ群は拡大側へ移動するように構成されていることが望ましい。 The projection zoom lens of the present invention is more specifically,
A negative first lens group, a positive second lens group, and a positive third lens group are arranged in order from the magnification side,
When zooming, the first lens group, the second lens group, and the third lens group move independently as a moving group,
It is desirable that the first lens group move to the reduction side and the second lens group and the third lens group move to the enlargement side when zooming from the wide-angle end to the telephoto end.
　あるいは、本発明の投写用ズームレンズはより具体的に、
　拡大側より順に実質的に、負の第１レンズ群、正の第２レンズ群、正の第３レンズ群および正の第４レンズ群が配列されてなり、
　変倍に際し前記第１レンズ群、第２レンズ群、第３レンズ群および第４レンズ群が移動群として各々独立して移動し、
　広角端から望遠端まで変倍する際に前記第１レンズ群は縮小側に移動し、前記第２レンズ群、前記第３レンズ群および前記第４レンズ群は拡大側へ移動するように構成されてもよい。 Alternatively, the zoom lens for projection according to the present invention is more specifically,
A negative first lens group, a positive second lens group, a positive third lens group, and a positive fourth lens group are arranged in sequence from the magnification side,
When zooming, the first lens group, the second lens group, the third lens group, and the fourth lens group move independently as a moving group,
When zooming from the wide-angle end to the telephoto end, the first lens group moves to the reduction side, and the second lens group, the third lens group, and the fourth lens group move to the enlargement side. May be.
　なお、本発明の投写用ズームレンズが上述のように４群構成とされる場合、第２レンズ群や第３レンズ群はそれぞれ１枚の単レンズで構成されることが望ましい。 When the projection zoom lens according to the present invention has a four-group configuration as described above, it is desirable that each of the second lens group and the third lens group is configured by a single lens.
　さらに、本発明の投写用ズームレンズにおいては、広角端における全系の焦点距離をｆwとし、広角端における全系のバックフォーカス（空気換算距離）をＢｆwとして、下記条件式（３）
　　１．０＜Ｂｆw ／fw 　・・・（３）
が満たされていることが望ましい。 Furthermore, in the projection zoom lens according to the present invention, the focal length of the entire system at the wide-angle end is fw, and the back focus (air conversion distance) of the entire system at the wide-angle end is Bfw. The following conditional expression (3)
1.0 <Bfw / fw (3)
It is desirable that
　また、本発明の投写用ズームレンズにおいては、最も縮小側のレンズ面における最大有効光束高が、縮小側の最大像高より小さいことが望ましい。 Further, in the projection zoom lens according to the present invention, it is desirable that the maximum effective luminous flux height on the lens surface on the most reduction side is smaller than the maximum image height on the reduction side.
　他方、本発明の投写型表示装置は、光源と、ライトバルブと、前記光源からの光束を前記ライトバルブへ導く照明光学部とに加えて、以上説明した本発明による投写用ズームレンズを備え、前記光源からの光束を前記ライトバルブで光変調し、前記投写用ズームレンズによりスクリーンに投写する構成を有することを特徴とするものである。 On the other hand, the projection display device of the present invention includes the projection zoom lens according to the present invention described above in addition to the light source, the light valve, and the illumination optical unit that guides the light beam from the light source to the light valve. The light beam from the light source is optically modulated by the light valve and projected onto a screen by the projection zoom lens.
　本発明の投写用ズームレンズにおいては、移動群として３群ないし４群のレンズ群を移動させて変倍動作を行う投写用ズームレンズにおいて、最も拡大側のレンズ群は負の屈折力を有する移動群から構成され、最も縮小側のレンズ群は正の屈折力を有する移動群から構成された上で、最も拡大側のレンズ群である第１レンズ群Ｇ１が実質的に２枚のレンズから構成されている。このように、一般にレンズ径が大きくなる最も拡大側のレンズ群を、２枚という少ないレンズ枚数で構成することにより、投写用ズームレンズを安価に形成可能となる。 In the projection zoom lens according to the present invention, in the projection zoom lens that performs zooming operation by moving the third to fourth lens groups as the moving group, the most enlarged lens group has a negative refractive power. The first lens group G1, which is the most magnified lens group, is substantially composed of two lenses. The most demagnifying lens group is composed of a moving group having a positive refractive power. Has been. As described above, the zoom lens for projection can be formed at low cost by configuring the lens group on the most enlarged side having a large lens diameter with a small number of lenses of two.
　しかし、そのようにしてコストメリットが得られる半面、レンズ枚数を少なく抑えたことにより、歪曲収差などの軸外収差が大きくなる可能性があるが、本発明の投写用ズームレンズは、以下の通りにして大きな収差の発生が防止されている。すなわち本発明の投写用ズームレンズにおいては、前記条件式（１）が満足されていることから、レンズ枚数削減により発生する歪曲収差などの軸外収差を良好に補正可能になり、さらに、縮小側のレンズ群のパワーバランスを向上させて像面湾曲なども良好に補正可能となる。 However, while the cost merit can be obtained in this way, there is a possibility that off-axis aberrations such as distortion aberration may be increased by reducing the number of lenses, but the projection zoom lens of the present invention is as follows. Thus, the occurrence of large aberrations is prevented. That is, in the projection zoom lens according to the present invention, since the conditional expression (1) is satisfied, it is possible to satisfactorily correct off-axis aberrations such as distortion caused by the reduction in the number of lenses, and further, on the reduction side. It is possible to improve the power balance of the lens group and correct the field curvature and the like.
　より詳しく説明すると、fm／fwの値が下限値の－３．５以下の場合は、最も拡大側のレンズ群のパワーが弱くなり過ぎることから、レンズ系の大型化につながる。逆にfm／fwの値が上限値の－１．０以上の場合は、最も拡大側のレンズ群のパワーが強くなり過ぎることから、歪曲収差などの諸収差の補正が困難になる。条件式（１）が満足されている場合は以上の不具合を防止して、高いズーム比を確保しながら、レンズ系の小型化および低コスト化を実現し、また諸収差、特に軸外収差を良好に補正可能となる。 More specifically, when the value of fm / fw is −3.5 or less, which is the lower limit, the power of the lens unit on the most magnified side becomes too weak, leading to an increase in the size of the lens system. On the other hand, when the value of fm / fw is −1.0 or more, which is the upper limit value, the power of the lens group on the most magnified side becomes too strong, and it becomes difficult to correct various aberrations such as distortion. When the conditional expression (1) is satisfied, the above-mentioned problems are prevented, a high zoom ratio is ensured, the lens system is reduced in size and cost, and various aberrations, particularly off-axis aberrations are reduced. It can be corrected satisfactorily.
　また、本発明の投写用ズームレンズにおいて特に、最も拡大側のレンズ群が拡大側より順に、少なくとも１面が非球面である非球面レンズおよび、両凹レンズを配置して構成されている場合は、以下の効果を得ることができる。すなわち、最も拡大側のレンズ群の最も拡大側位置に非球面レンズを配置することで、軸外収差、特に歪曲収差の補正が効果的になされるようになる。また、このレンズ群の縮小側位置に負の両凹レンズを配置することで、全体として適切な負のパワーを持たせることができ、非点収差などの軸外収差の補正が効果的になされるようになる。 Further, in the projection zoom lens of the present invention, in particular, when the lens group on the most enlargement side is configured by arranging an aspherical lens having at least one aspherical surface and a biconcave lens in order from the enlargement side, The following effects can be obtained. That is, by disposing an aspheric lens at the most magnified position of the most magnified lens group, it is possible to effectively correct off-axis aberrations, particularly distortion. Further, by arranging a negative biconcave lens at the reduction side position of this lens group, it is possible to give an appropriate negative power as a whole, and it is possible to effectively correct off-axis aberrations such as astigmatism. It becomes like this.
　そして、特に上記非球面レンズがプラスチックレンズとされる一方、上記両凹レンズがガラスレンズとされた場合は、以下の効果を得ることができる。すなわちこの構成により、収差補正機能は非球面プラスチックレンズに、必要なパワーはガラスレンズに各々分担させることができ、これにより収差補正機能を十分発揮させつつ、熱的な変化に影響され難いレンズ系を構築することが可能になる。また、１つのレンズをプラスチック材から形成することで、生産性およびコストの点で有利となる。 In particular, when the aspheric lens is a plastic lens, and the biconcave lens is a glass lens, the following effects can be obtained. In other words, with this configuration, the aberration correction function can be assigned to the aspheric plastic lens, and the necessary power can be assigned to the glass lens, thereby making the lens system less susceptible to thermal changes while fully exhibiting the aberration correction function. It becomes possible to build. Further, forming one lens from a plastic material is advantageous in terms of productivity and cost.
　また、本発明の投写用ズームレンズにおいて特に前記条件式（２）が満足されている場合は、以下の効果を得ることができる。すなわち条件式（２）は、像面湾曲（特にサジタル像面の湾曲)を良好に補正するための条件を規定したものであり、ｆr／ｆwの値が２．０以下になっても、また５０．０以上になっても像面湾曲を良好に補正することが困難になる。条件式（２）が満足されている場合は、以上の不具合を防止して、像面湾曲を良好に補正可能となる。 In the zoom lens for projection according to the present invention, particularly when the conditional expression (2) is satisfied, the following effects can be obtained. That is, the conditional expression (2) defines a condition for satisfactorily correcting the curvature of field (particularly the curvature of the sagittal image surface), and even if the value of fr / fw becomes 2.0 or less, Even if it becomes 50.0 or more, it becomes difficult to correct the curvature of field well. When the conditional expression (2) is satisfied, the above problems can be prevented and the field curvature can be corrected well.
　また、本発明の投写用ズームレンズにおいて特に、最も縮小側のレンズ群が拡大側より順に、両凹レンズ、正レンズ、拡大側に凹面を向けた負レンズを有している場合は、上に述べた条件式（２）を満足することで得られる作用、効果をさらに顕著なものとすることができ、さらには、ズーミングによる球面収差の変動を小さく抑えることも可能になる。 In the projection zoom lens of the present invention, in particular, when the lens group on the most reduction side has a biconcave lens, a positive lens, and a negative lens with a concave surface directed toward the enlargement side in order from the enlargement side, the above is described. Further, the function and effect obtained by satisfying the conditional expression (2) can be made more remarkable, and further, the fluctuation of spherical aberration due to zooming can be suppressed to a small value.
　また、本発明の投写用ズームレンズが特に、拡大側より順に実質的に、負の第１レンズ群、正の第２レンズ群および正の第３レンズ群が配列されてなり、変倍に際し前記第１レンズ群、第２レンズ群および第３レンズ群が移動群として各々独立して移動し、広角端から望遠端まで変倍する際に前記第１レンズ群は縮小側に移動し、前記第２レンズ群および前記第３レンズ群は拡大側へ移動するように構成されている場合は、レンズ系全体を大型化せずに、高いズーム比を確保することが可能になる。 Further, the projection zoom lens according to the present invention has a negative first lens group, a positive second lens group, and a positive third lens group, which are substantially arranged in order from the enlargement side. The first lens group, the second lens group, and the third lens group move independently as a moving group, and when zooming from the wide angle end to the telephoto end, the first lens group moves to the reduction side, and the first lens group When the two lens group and the third lens group are configured to move to the enlargement side, it is possible to ensure a high zoom ratio without increasing the size of the entire lens system.
　また、本発明の投写用ズームレンズが特に、拡大側より順に実質的に、負の第１レンズ群、正の第２レンズ群、正の第３レンズ群および正の第４レンズ群が配列されてなり、変倍に際し前記第１レンズ群、第２レンズ群、第３レンズ群および第４レンズ群が移動群として各々独立して移動し、広角端から望遠端まで変倍する際に前記第１レンズ群は縮小側に移動し、前記第２レンズ群、前記第３レンズ群および前記第４レンズ群は拡大側へ移動するように構成されている場合も、レンズ系全体を大型化せずに、高いズーム比を確保することが可能になる。 In the projection zoom lens according to the present invention, in particular, a negative first lens group, a positive second lens group, a positive third lens group, and a positive fourth lens group are arranged in order from the magnification side. When zooming, the first lens group, the second lens group, the third lens group, and the fourth lens group move independently as a moving group, and when zooming from the wide-angle end to the telephoto end, Even when one lens group is moved to the reduction side and the second lens group, the third lens group, and the fourth lens group are moved to the enlargement side, the entire lens system is not enlarged. In addition, a high zoom ratio can be ensured.
　また、本発明の投写用ズームレンズが上述のような４群構成とされる場合において、特に第２レンズ群や第３レンズ群がそれぞれ１枚の単レンズで構成されていれば、レンズ枚数を特に少なく抑えて、より高いコストダウン効果が得られる。 Further, when the projection zoom lens according to the present invention has the four-group configuration as described above, the number of lenses can be reduced particularly when each of the second lens group and the third lens group is composed of one single lens. In particular, it is possible to obtain a higher cost reduction effect with a small amount.
　また、本発明の投写用ズームレンズにおいて、特に前述の条件式（３）が満足されている場合は、以下の効果を得ることができる。すなわち、Ｂｆw ／fwの値が１．０以下になると、通常投写用ズームレンズに近接させて配置される照明光学系の配置が困難になるが、条件式（３）が満足されている場合はそのような不具合を防止して、照明光学系の配置が容易化される。 In the projection zoom lens according to the present invention, the following effects can be obtained particularly when the above-described conditional expression (3) is satisfied. That is, when the value of Bfwｆ / fw is 1.0 or less, it is difficult to place an illumination optical system that is placed close to the normal projection zoom lens. However, if conditional expression (3) is satisfied, Such an inconvenience is prevented, and the arrangement of the illumination optical system is facilitated.
　また、本発明の投写用ズームレンズにおいて特に、最も縮小側のレンズ面における最大有効光束高が、縮小側の最大像高より小さくなっている場合は、十分なレンズバックを確保でき、また最も縮小側のレンズ群のレンズ径を小型化することも可能になる。 In the zoom lens for projection according to the present invention, in particular, when the maximum effective luminous flux height on the lens surface on the most reduction side is smaller than the maximum image height on the reduction side, a sufficient lens back can be secured and the most reduction can be achieved. It is also possible to reduce the lens diameter of the lens group on the side.
　他方、本発明の投写型表示装置は、投写用ズームレンズとして以上述べた通りの本発明のズームレンズが適用されたものであるので、高いズーム比で高画質の画像を表示可能となる。 On the other hand, since the zoom lens of the present invention as described above is applied as the projection zoom lens, the projection display apparatus of the present invention can display a high-quality image with a high zoom ratio.
本発明の実施例１に係る投写用ズームレンズのレンズ構成を示す断面図Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 1 of this invention. 本発明の実施例２に係る投写用ズームレンズのレンズ構成を示す断面図Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 2 of this invention. 本発明の実施例３に係る投写用ズームレンズのレンズ構成を示す断面図Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 3 of this invention. 本発明の実施例４に係る投写用ズームレンズのレンズ構成を示す断面図Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 4 of this invention. 本発明の実施例５に係る投写用ズームレンズのレンズ構成を示す断面図Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 5 of this invention. 本発明の実施例６に係る投写用ズームレンズのレンズ構成を示す断面図Sectional drawing which shows the lens structure of the zoom lens for projection which concerns on Example 6 of this invention. （Ａ）～（Ｌ）は上記実施例１に係る投写用ズームレンズの各収差図(A) to (L) are aberration diagrams of the projection zoom lens according to Example 1 described above. （Ａ）～（Ｌ）は上記実施例２に係る投写用ズームレンズの各収差図(A) to (L) are aberration diagrams of the projection zoom lens according to Example 2 described above. （Ａ）～（Ｌ）は上記実施例３に係る投写用ズームレンズの各収差図(A) to (L) are aberration diagrams of the projection zoom lens according to Example 3 described above. （Ａ）～（Ｌ）は上記実施例４に係る投写用ズームレンズの各収差図(A) to (L) are aberration diagrams of the projection zoom lens according to Example 4 described above. （Ａ）～（Ｌ）は上記実施例５に係る投写用ズームレンズの各収差図(A) to (L) are aberration diagrams of the projection zoom lens according to Example 5 described above. （Ａ）～（Ｌ）は上記実施例６に係る投写用ズームレンズの各収差図(A) to (L) are aberration diagrams of the projection zoom lens according to Example 6 described above. 本発明の一実施形態に係る投写型表示装置の概略構成図1 is a schematic configuration diagram of a projection display device according to an embodiment of the present invention.
　以下、本発明の実施形態について図面を参照して詳細に説明する。まず、図１～図６を参照して、本発明の投写用ズームレンズの実施形態について説明する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, an embodiment of a projection zoom lens according to the present invention will be described with reference to FIGS.
　図１は、本発明の一実施形態に係る投写用ズームレンズを変倍操作させたときの広角端および望遠端における、各レンズ群の移動位置を示す断面図であり、後述する実施例１の投写用ズームレンズに対応している。また図２～６も、同様にして本発明の実施形態に係る別の構成例を示す断面図であり、それぞれ後述する実施例２～６の投写用ズームレンズに対応している。なおこれらの図では、広角端から望遠端へ変化する際のレンズ群の移動方向を、各位置間の矢印で概略的に示している。 FIG. 1 is a cross-sectional view showing the movement position of each lens group at the wide-angle end and the telephoto end when the zooming lens for projection according to an embodiment of the present invention is operated for zooming. Compatible with projection zoom lenses. 2 to 6 are also sectional views showing other configuration examples according to the embodiment of the present invention, and correspond to projection zoom lenses of Examples 2 to 6, which will be described later, respectively. In these drawings, the moving direction of the lens group when changing from the wide-angle end to the telephoto end is schematically shown by arrows between the positions.
　図１、２に各々示す実施例１、２の投写用ズームレンズは３群構成とされたものであり、それに対して図３～６に各々示す実施例３～６の投写用ズームレンズは４群構成とされたものである。 The projection zoom lenses of Examples 1 and 2 shown in FIGS. 1 and 2 each have a three-group configuration, whereas the projection zoom lenses of Examples 3 to 6 shown in FIGS. It is a group structure.
　＜３群構成の実施形態＞
　まず、主に図１に示す構成を例に取って、３群構成とされた投写用ズームレンズの実施形態について説明する。本実施形態の投写用ズームレンズは、例えばライトバルブに表示された画像情報をスクリーンへ投写する投写レンズとして使用可能である。図１では、図の左側を拡大側、右側を縮小側とし、投写型表示装置に搭載される場合を想定して、平行平板ＰＰも合わせて示してある。すなわち、通常はこの平行平板ＰＰの縮小側の面に、ライトバルブの画像表示面が配置される。これは、他の図２～図６の構成においても同様である。 <Embodiment having a three-group configuration>
First, an embodiment of a projection zoom lens having a three-group configuration will be described mainly using the configuration shown in FIG. 1 as an example. The projection zoom lens of the present embodiment can be used as a projection lens that projects image information displayed on a light valve onto a screen, for example. In FIG. 1, the left side of the drawing is the enlarged side, and the right side is the reduced side, and the parallel plate PP is also shown assuming that it is mounted on a projection display device. That is, the image display surface of the light valve is usually arranged on the reduction side surface of the parallel plate PP. The same applies to the other configurations shown in FIGS.
　投写型表示装置においては、ライトバルブの画像表示面で画像情報を与えられた光束が、平行平板ＰＰを介して投写用ズームレンズに入射する。そして、この投写用ズームレンズにより、紙面左側方向に配置される図示外のスクリーン上に、上記画像情報に基づく画像が投写表示される。 In the projection display device, a light beam given image information on the image display surface of the light valve enters the projection zoom lens via the parallel plate PP. The projection zoom lens projects and displays an image based on the image information on a screen (not shown) arranged in the left direction of the drawing.
　なおライトバルブの画像表示面は、平行平板ＰＰの縮小側の面から離して配置されても構わない。また、上述のように投写用ズームレンズに対して１つのライトバルブの画像表示面を配置する他、光源からの光束を色分離光学系により３原色に分離し、各原色用に３つのライトバルブを配設して、フルカラー画像を表示できるように構成してもよい。 Note that the image display surface of the light valve may be arranged away from the reduction side surface of the parallel plate PP. In addition to arranging the image display surface of one light valve for the projection zoom lens as described above, the light beam from the light source is separated into three primary colors by a color separation optical system, and three light valves are used for each primary color. May be arranged so that a full-color image can be displayed.
　本実施形態に係る投写用ズームレンズは、最も拡大側に配置された第１レンズ群Ｇ１、この第１レンズ群Ｇ１よりも縮小側に配置された第２レンズ群Ｇ２および、最も縮小側に配置された第３レンズ群Ｇ３のみを実質的なレンズ群として備えて構成されている。ここで、第１レンズ群Ｇ１は負の屈折力を有するものとされ、第２レンズ群Ｇ２および第３レンズ群Ｇ３は各々正の屈折力を有するものとされている。そして第１レンズ群Ｇ１、第２レンズ群Ｇ２および第３レンズ群Ｇ３は、変倍の際にそれぞれ独立して移動するように構成されている。 The projection zoom lens according to this embodiment includes a first lens group G1 disposed closest to the enlargement side, a second lens group G2 disposed closer to the reduction side than the first lens group G1, and disposed closest to the reduction side. Only the third lens group G3 is provided as a substantial lens group. Here, the first lens group G1 has a negative refractive power, and the second lens group G2 and the third lens group G3 each have a positive refractive power. The first lens group G1, the second lens group G2, and the third lens group G3 are configured to move independently during zooming.
　図１に示す例では、第１レンズ群Ｇ１は２枚のレンズ（第１レンズＬ１および第２レンズＬ２）からなり、第２レンズ群Ｇ２は２枚のレンズ（第３レンズＬ３および第４レンズＬ４）からなり、第３レンズ群Ｇ３は４枚のレンズ（第５レンズＬ５～第８レンズＬ８）からなる。図２に示す例は、レンズ枚数に関しては、第３レンズ群Ｇ３が５枚のレンズ（第５レンズＬ５～第９レンズＬ９）からなる点において図１の例と相違している。 In the example shown in FIG. 1, the first lens group G1 includes two lenses (first lens L1 and second lens L2), and the second lens group G2 includes two lenses (third lens L3 and fourth lens). L4), and the third lens group G3 includes four lenses (fifth lens L5 to eighth lens L8). The example shown in FIG. 2 is different from the example of FIG. 1 in that the third lens group G3 includes five lenses (fifth lens L5 to ninth lens L9) with respect to the number of lenses.
　そしてこの投写用ズームレンズは、第１レンズ群Ｇ１を移動させてフォーカシングを行うように構成されている。 The projection zoom lens is configured to perform focusing by moving the first lens group G1.
　本実施形態の投写用ズームレンズにおいては上述の通り、最も拡大側のレンズ群である第１レンズ群Ｇ１が実質的に２枚のレンズから構成されている。このように、一般にレンズ径が大きくなる最も拡大側のレンズ群を、２枚という少ないレンズ枚数で構成することにより、投写用ズームレンズを安価に形成可能となる。 In the zoom lens for projection according to the present embodiment, as described above, the first lens group G1, which is the most magnified lens group, is substantially composed of two lenses. As described above, the zoom lens for projection can be formed at low cost by configuring the lens group on the most enlarged side having a large lens diameter with a small number of lenses of two.
　しかし、そのようにしてコストメリットが得られる半面、レンズ枚数を少なく抑えたことにより、歪曲収差などの軸外収差が大きくなる可能性がある。この点に鑑みて本実施形態においては、広角端における全系の焦点距離をｆw、第１レンズ群Ｇ１の焦点距離をｆmとしたとき、下記条件式（１）が満足されている。 However, on the other hand, it is possible to obtain cost merit in this way, but by reducing the number of lenses, off-axis aberrations such as distortion may be increased. In view of this point, in this embodiment, when the focal length of the entire system at the wide angle end is fw and the focal length of the first lens group G1 is fm, the following conditional expression (1) is satisfied.
　　－３．５＜ fm／fw ＜－１．０・・・（１）
　ここで、条件式（１）が規定する条件（つまり文字式の部分）の値を、後述する条件式（２）、（３）が各々規定する条件の値と共に、表１９において、実施例毎にまとめて示してある。なお表１９では、全系の焦点距離ｆwを１．００として示してあるので、fm、frおよびＢｆwの値がすなわち、各々fm／fw、ｆr／ｆwおよびＢｆw ／fwの値となる。 -3.5 <fm / fw <-1.0 (1)
Here, the values of the conditions defined by the conditional expression (1) (that is, the character expression portion) are shown in Table 19 together with the values of the conditions defined by the conditional expressions (2) and (3) described later for each example. Are shown together. In Table 19, since the focal length fw of the entire system is shown as 1.00, the values of fm, fr and Bfw are values of fm / fw, fr / fw and Bfw / fw, respectively.
　上記の条件式（１）が満足されていることから、レンズ枚数削減により発生する歪曲収差などの軸外収差を良好に補正可能になり、さらに、縮小側のレンズ群のパワーバランスを向上させて像面湾曲なども良好に補正可能となる。 Since the above conditional expression (1) is satisfied, it becomes possible to satisfactorily correct off-axis aberrations such as distortion caused by the reduction in the number of lenses, and further improve the power balance of the lens unit on the reduction side. Field curvature and the like can be corrected well.
　より詳しく説明すると、fm／fwの値が下限値の－３．５以下の場合は、第１レンズ群Ｇ１のパワーが弱くなり過ぎることから、レンズ系の大型化につながる。逆にfm／fwの値が上限値の－１．０以上の場合は、第１レンズ群Ｇ１のパワーが強くなり過ぎることから、歪曲収差などの諸収差の補正が困難になる。条件式（１）が満足されている場合は以上の不具合を防止して、高いズーム比を確保しながら、レンズ系の小型化および低コスト化を実現し、また諸収差、特に軸外収差を良好に補正可能となる。 More specifically, when the value of fm / fw is −3.5 or less, which is the lower limit value, the power of the first lens group G1 becomes too weak, leading to an increase in the size of the lens system. On the other hand, when the value of fm / fw is −1.0 or more, which is the upper limit value, the power of the first lens group G1 becomes too strong, and it becomes difficult to correct various aberrations such as distortion. When the conditional expression (1) is satisfied, the above-mentioned problems are prevented, a high zoom ratio is ensured, the lens system is reduced in size and cost, and various aberrations, particularly off-axis aberrations are reduced. It can be corrected satisfactorily.
　さらに、本実施形態の投写用ズームレンズにおいては、最も拡大側のレンズ群である第１レンズ群Ｇ１が拡大側より順に、少なくとも１面が非球面である非球面レンズ（第１レンズＬ１）および、両凹レンズ（第２レンズＬ２）を配置して構成されているので、以下の効果が得られる。すなわち、最も拡大側のレンズ群の最も拡大側位置に非球面レンズを配置することで、軸外収差、特に歪曲収差の補正が効果的になされるようになる。また、このレンズ群の縮小側位置に負の両凹レンズを配置することで、全体として適切な負のパワーを持たせることができ、非点収差などの軸外収差の補正が効果的になされるようになる。 Furthermore, in the projection zoom lens according to the present embodiment, the first lens group G1, which is the lens group closest to the magnification side, in order from the magnification side, an aspherical lens (first lens L1) having at least one aspheric surface, and Since the biconcave lens (second lens L2) is arranged, the following effects can be obtained. That is, by disposing an aspheric lens at the most magnified position of the most magnified lens group, it is possible to effectively correct off-axis aberrations, particularly distortion. Further, by arranging a negative biconcave lens at the reduction side position of this lens group, it is possible to give an appropriate negative power as a whole, and it is possible to effectively correct off-axis aberrations such as astigmatism. It becomes like this.
　また、本実施形態の投写用ズームレンズにおいては、非球面レンズである第１レンズＬ１がプラスチックレンズとされる一方、両凹レンズである第２レンズＬ２はガラスレンズとされており、それにより以下の効果が得られる。すなわちこの構成により、収差補正機能は非球面プラスチックレンズに、必要なパワーはガラスレンズに各々分担させることができ、これにより収差補正機能を十分発揮させつつ、熱的な変化に影響され難いレンズ系を構築することが可能になる。また、１つのレンズをプラスチック材から形成することで、生産性およびコストの点で有利となる。 In the projection zoom lens according to the present embodiment, the first lens L1 that is an aspherical lens is a plastic lens, while the second lens L2 that is a biconcave lens is a glass lens. An effect is obtained. In other words, with this configuration, the aberration correction function can be assigned to the aspheric plastic lens, and the necessary power can be assigned to the glass lens, thereby making the lens system less susceptible to thermal changes while fully exhibiting the aberration correction function. It becomes possible to build. Further, forming one lens from a plastic material is advantageous in terms of productivity and cost.
　また、本実施形態の投写用ズームレンズにおいては、広角端における全系の焦点距離をｆw、最も縮小側のレンズ群である第３レンズ群Ｇ３の焦点距離をfrとして、下記条件式（２）が満足されている。 In the projection zoom lens according to the present embodiment, the focal length of the entire system at the wide-angle end is fw, and the focal length of the third lens group G3, which is the most reducing lens group, is fr. Is satisfied.
　　２．０＜ ｆr／ｆw ＜５０．０・・・（２）
　この条件式（２）は、像面湾曲（特にサジタル像面の湾曲)を良好に補正するための条件を規定したものであり、ｆr／ｆwの値が２．０以下になっても、また５０．０以上になっても像面湾曲を良好に補正することが困難になる。条件式（２）が満足されている場合は、以上の不具合を防止して、像面湾曲を良好に補正可能となる。 2.0 <fr / fw <50.0 (2)
This conditional expression (2) defines the conditions for satisfactorily correcting the curvature of field (particularly the curvature of the sagittal image plane), and even if the value of fr / fw is 2.0 or less, Even if it becomes 50.0 or more, it becomes difficult to correct the curvature of field well. When the conditional expression (2) is satisfied, the above problems can be prevented and the field curvature can be corrected well.
　また、本実施形態の投写用ズームレンズにおいては、最も縮小側のレンズ群である第３レンズ群Ｇ３が拡大側より順に、両凹レンズ（第５レンズＬ５）、正レンズ（第６レンズＬ６）、拡大側に凹面を向けた負レンズ（第７レンズＬ７）を有している。このようなレンズ配列とすることにより、上に述べた条件式（２）を満足することで得られる作用、効果をさらに顕著なものとすることができ、さらには、ズーミングによる球面収差の変動を小さく抑えることも可能になる。 In the projection zoom lens according to the present embodiment, the third lens group G3, which is the most reducing lens group, is arranged in order from the enlargement side, a biconcave lens (fifth lens L5), a positive lens (sixth lens L6), A negative lens (seventh lens L7) having a concave surface on the enlargement side is provided. By using such a lens arrangement, the function and effect obtained by satisfying the conditional expression (2) described above can be made more remarkable, and further, the fluctuation of spherical aberration due to zooming can be reduced. It can also be kept small.
　また、本実施形態の投写用ズームレンズにおいては、広角端における全系の焦点距離をｆw、広角端における全系のバックフォーカス（空気換算距離）をＢｆwとして、下記条件式（３）が満足されている。 In the projection zoom lens according to the present embodiment, the following conditional expression (3) is satisfied, where the focal length of the entire system at the wide-angle end is fw and the back focus (air conversion distance) of the entire system at the wide-angle end is Bfw. ing.
　　１．０＜Ｂｆw ／fw 　・・・（３）
　このＢｆw ／fwの値が１．０以下になると、通常投写用ズームレンズに近接させて配置される照明光学系の配置が困難になるが、条件式（３）が満足されている場合はそのような不具合を防止して、照明光学系の配置が容易化される。 1.0 <Bfw / fw (3)
If the value of Bfw / fw is 1.0 or less, it is difficult to place an illumination optical system that is placed close to the normal projection zoom lens. However, if the conditional expression (3) is satisfied, Such an inconvenience is prevented, and the arrangement of the illumination optical system is facilitated.
　また、本実施形態の投写用ズームレンズにおいては、後に具体的な数値を示す通り、最も縮小側のレンズ面（図１の例では第８レンズＬ８の、そして図２の例では第９レンズＬ９の各縮小側のレンズ面）における最大有効光束高が、縮小側の最大像高より小さくなっている。それにより、十分なレンズバックを確保でき、また最も縮小側のレンズ群のレンズ径を小型化することも可能になる。 In the projection zoom lens according to the present embodiment, as will be described later with specific numerical values, the lens surface on the most reduction side (the eighth lens L8 in the example of FIG. 1 and the ninth lens L9 in the example of FIG. 2). The maximum effective luminous flux height on each reduction side lens surface is smaller than the maximum image height on the reduction side. Thereby, a sufficient lens back can be secured, and the lens diameter of the lens group on the most reduction side can be reduced.
　また、本実施形態の投写用ズームレンズは、変倍に際して３つのレンズ群Ｇ１、Ｇ２およびＧ３が移動群として各々独立して移動し、そして広角端から望遠端まで変倍する際に第１レンズ群Ｇ１は縮小側に移動し、第２レンズ群Ｇ２および第３レンズ群Ｇ３は拡大側へ移動するように構成されている。このような構成とすることにより、レンズ系全体を大型化せずに、高いズーム比を確保することが可能になる。 In the projection zoom lens according to the present embodiment, the three lens groups G1, G2, and G3 each move independently as a moving group during zooming, and the first lens when zooming from the wide-angle end to the telephoto end. The group G1 moves to the reduction side, and the second lens group G2 and the third lens group G3 move to the enlargement side. With such a configuration, it is possible to ensure a high zoom ratio without increasing the size of the entire lens system.
　以上、＜３群構成の実施形態＞の項の中で説明したことは、第３レンズ群Ｇ３を構成するレンズ枚数の相違を除いて、基本的に、図１および２の構成の双方について言えるものである。 As described above, what has been described in the section <Embodiment of the three-group configuration> can be basically applied to both the configurations of FIGS. 1 and 2 except for the difference in the number of lenses constituting the third lens group G3. Is.
　＜４群構成の実施形態＞
　次に、図３～図６に示す４群構成の投写用ズームレンズの実施形態について、主に図３の構成を例に取って説明する。なお、本実施形態の投写用ズームレンズを投写型表示装置に適用することに関しては、前述した３群構成の投写用ズームレンズを適用する場合と基本的に同じことが言えるので、その点についての重複した説明は省略する。 <Embodiment with a four-group configuration>
Next, an embodiment of the projection zoom lens having a four-group configuration shown in FIGS. 3 to 6 will be described mainly by taking the configuration of FIG. 3 as an example. Note that the application of the projection zoom lens of the present embodiment to the projection display device is basically the same as the case of applying the projection zoom lens having the three-group configuration described above. A duplicate description is omitted.
　本実施形態に係る投写用ズームレンズは、最も拡大側に配置された第１レンズ群Ｇ１、この第１レンズ群Ｇ１よりも縮小側に配置された第２レンズ群Ｇ２、この第２レンズ群Ｇ２よりも縮小側に配置された第３レンズ群Ｇ３および、最も縮小側に配置された第４レンズ群Ｇ４のみを実質的なレンズ群として備えて構成されている。ここで、第１レンズ群Ｇ１は負の屈折力を有するものとされ、第２レンズ群Ｇ２、第３レンズ群Ｇ３および第４レンズ群Ｇ４は各々正の屈折力を有するものとされている。そして第１レンズ群Ｇ１、第２レンズ群Ｇ２、第３レンズ群Ｇ３および第４レンズ群Ｇ４は、変倍の際にそれぞれ独立して移動するように構成されている。 The projection zoom lens according to the present embodiment includes a first lens group G1 that is disposed closest to the enlargement side, a second lens group G2 that is disposed closer to the reduction side than the first lens group G1, and the second lens group G2. Only the third lens group G3 disposed on the reduction side and the fourth lens group G4 disposed on the most reduction side are provided as substantial lens groups. Here, the first lens group G1 has a negative refractive power, and the second lens group G2, the third lens group G3, and the fourth lens group G4 each have a positive refractive power. The first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 are configured to move independently during zooming.
　図３に示す例では、第１レンズ群Ｇ１は２枚のレンズ（第１レンズＬ１および第２レンズＬ２）からなり、第２レンズ群Ｇ２は１枚のレンズ（第３レンズＬ３）からなり、第３レンズ群Ｇ３は１枚のレンズ（第４レンズＬ４）からなる。以上は、図４～６に示す各例においても同様である。一方第４レンズ群Ｇ４は、図３に示す例では４枚のレンズ（第５レンズＬ５～第８レンズＬ８）からなり、図４に示す例では５枚のレンズ（第５レンズＬ５～第９レンズＬ９）からなり、図５および図６に示す例では６枚のレンズ（第５レンズＬ５～第１０レンズＬ１０）からなる。 In the example shown in FIG. 3, the first lens group G1 includes two lenses (first lens L1 and second lens L2), and the second lens group G2 includes one lens (third lens L3). The third lens group G3 includes one lens (fourth lens L4). The same applies to the examples shown in FIGS. On the other hand, the fourth lens group G4 includes four lenses (fifth lens L5 to eighth lens L8) in the example shown in FIG. 3, and five lenses (fifth lens L5 to ninth lens L8) in the example shown in FIG. Lens L9), and in the example shown in FIG. 5 and FIG. 6, it consists of six lenses (fifth lens L5 to tenth lens L10).
　そしてこの投写用ズームレンズは、第１レンズ群Ｇ１を移動させてフォーカシングを行うように構成されている。 The projection zoom lens is configured to perform focusing by moving the first lens group G1.
　本実施形態の投写用ズームレンズにおいては上述の通り、最も拡大側のレンズ群である第１レンズ群Ｇ１が実質的に２枚のレンズから構成されている。このように、一般にレンズ径が大きくなる最も拡大側のレンズ群を、２枚という少ないレンズ枚数で構成することにより、投写用ズームレンズを安価に形成可能となる。 In the zoom lens for projection according to the present embodiment, as described above, the first lens group G1, which is the most magnified lens group, is substantially composed of two lenses. As described above, the zoom lens for projection can be formed at low cost by configuring the lens group on the most enlarged side having a large lens diameter with a small number of lenses of two.
　また本実施形態でも、広角端における全系の焦点距離をｆw、第１レンズ群Ｇ１の焦点距離をｆmとしたとき、前述した条件式（１）が満足されている（表１９参照）。それにより本実施形態でも、レンズ枚数削減により発生する歪曲収差などの軸外収差を良好に補正可能になり、さらに、縮小側のレンズ群のパワーバランスを向上させて像面湾曲なども良好に補正可能となる。その詳しい理由は先に詳しく述べた通りである。 Also in this embodiment, when the focal length of the entire system at the wide angle end is fw and the focal length of the first lens group G1 is fm, the above-described conditional expression (1) is satisfied (see Table 19). As a result, even in this embodiment, off-axis aberrations such as distortion caused by the reduction in the number of lenses can be corrected well, and the power balance of the lens unit on the reduction side is improved to correct field curvature and the like. It becomes possible. The detailed reason is as detailed above.
　また、本実施形態の投写用ズームレンズにおいても、最も拡大側のレンズ群である第１レンズ群Ｇ１が拡大側より順に、少なくとも１面が非球面である非球面レンズ（第１レンズＬ１）および、両凹レンズ（第２レンズＬ２）を配置して構成されているので、軸外収差、特に歪曲収差の補正が効果的になされ、そして非点収差などの軸外収差の補正が効果的になされる。その詳しい理由は先に詳しく述べた通りである。 Also in the projection zoom lens according to the present embodiment, the first lens group G1, which is the lens group closest to the magnification side, in order from the magnification side, an aspherical lens (first lens L1) having at least one aspherical surface and Since the biconcave lens (second lens L2) is arranged, off-axis aberrations, particularly distortion aberrations are effectively corrected, and off-axis aberrations such as astigmatism are effectively corrected. The The detailed reason is as detailed above.
　さらに、本実施形態の投写用ズームレンズにおいても、非球面レンズである第１レンズＬ１がプラスチックレンズとされる一方、両凹レンズである第２レンズＬ２はガラスレンズとされているので、収差補正機能を十分発揮させつつ、熱的な変化に影響され難いレンズ系を構築することが可能になる。また、１つのレンズをプラスチック材から形成することで、生産性およびコストの点で有利となる。 Further, in the projection zoom lens according to the present embodiment, the first lens L1 that is an aspheric lens is a plastic lens, while the second lens L2 that is a biconcave lens is a glass lens. It is possible to construct a lens system that is less susceptible to thermal changes while fully exhibiting the above. Further, forming one lens from a plastic material is advantageous in terms of productivity and cost.
　本実施形態の投写用ズームレンズにおいて、最も縮小側のレンズ群は第４レンズ群Ｇ４となるが、その焦点距離をfrとし、広角端における全系の焦点距離をｆwとすると、ここでも前記条件式（２）が満足されている（表１９参照）。したがって本実施形態でも、先に述べた３群構成の実施形態におけるのと同じ理由により、像面湾曲を良好に補正可能となる。 In the projection zoom lens according to the present embodiment, the lens group on the most reduction side is the fourth lens group G4. If the focal length is fr and the focal length of the entire system at the wide angle end is fw, the above conditions are also satisfied. Equation (2) is satisfied (see Table 19). Therefore, also in the present embodiment, the field curvature can be favorably corrected for the same reason as in the above-described three-group configuration embodiment.
　また、本実施形態の投写用ズームレンズにおいては、最も縮小側のレンズ群である第４レンズ群Ｇ４が拡大側より順に、両凹レンズ（第５レンズＬ５）、正レンズ（第６レンズＬ６）、拡大側に凹面を向けた負レンズ（第７レンズＬ７）を有している。このようなレンズ配列とすることにより、上に述べた条件式（２）を満足することで得られる作用、効果をさらに顕著なものとすることができ、さらには、ズーミングによる球面収差の変動を小さく抑えることも可能になる。 In the projection zoom lens according to the present embodiment, the fourth lens group G4, which is the lens group closest to the reduction side, is arranged in order from the enlargement side, a biconcave lens (fifth lens L5), a positive lens (sixth lens L6), A negative lens (seventh lens L7) having a concave surface on the enlargement side is provided. By using such a lens arrangement, the function and effect obtained by satisfying the conditional expression (2) described above can be made more remarkable, and further, the fluctuation of spherical aberration due to zooming can be reduced. It can also be kept small.
　また、本実施形態の投写用ズームレンズにおいても、広角端における全系の焦点距離をｆw、広角端における全系のバックフォーカス（空気換算距離）をＢｆwとして、前述した条件式（３）が満足されている。それにより、照明光学系の配置が容易化される。 Also in the projection zoom lens according to the present embodiment, the above-mentioned conditional expression (3) is satisfied, assuming that the focal length of the entire system at the wide-angle end is fw and the back focus (air conversion distance) of the entire system at the wide-angle end is Bfw. Has been. Thereby, the arrangement of the illumination optical system is facilitated.
　また、本実施形態の投写用ズームレンズにおいては、後に具体的な数値を示す通り、最も縮小側のレンズ面（図３の例では第８レンズＬ８の、図４の例では第９レンズＬ９の、そして図５、６の例では第１０レンズＬ１０の各縮小側のレンズ面）における最大有効光束高が、縮小側の最大像高より小さくなっている。それにより、十分なレンズバックを確保でき、また最も縮小側のレンズ群のレンズ径を小型化することも可能になる。 Further, in the projection zoom lens according to the present embodiment, as will be described later with specific numerical values, the lens surface closest to the reduction side (the eighth lens L8 in the example of FIG. 3 and the ninth lens L9 in the example of FIG. 4). In the examples of FIGS. 5 and 6, the maximum effective luminous flux height on each reduction side lens surface of the tenth lens L10 is smaller than the maximum image height on the reduction side. Thereby, a sufficient lens back can be secured, and the lens diameter of the lens group on the most reduction side can be reduced.
　また、本実施形態の投写用ズームレンズは、変倍に際し上記４つのレンズ群Ｇ１、Ｇ２、Ｇ３およびＧ４が移動群として各々独立して移動し、そして広角端から望遠端まで変倍する際に第１レンズ群Ｇ１は縮小側に移動し、第２レンズ群Ｇ２、第３レンズ群Ｇ３および第４レンズ群Ｇ４は拡大側へ移動するように構成されている。このような構成とすることにより、レンズ系全体を大型化せずに、高いズーム比を確保することが可能になる。 In the projection zoom lens according to the present embodiment, when zooming, the four lens groups G1, G2, G3, and G4 each move independently as a moving group, and when zooming from the wide-angle end to the telephoto end. The first lens group G1 moves to the reduction side, and the second lens group G2, the third lens group G3, and the fourth lens group G4 move to the enlargement side. With such a configuration, it is possible to ensure a high zoom ratio without increasing the size of the entire lens system.
　そして、上記第２レンズ群Ｇ２および第３レンズ群Ｇ３がそれぞれ１枚の単レンズから構成されているので、本実施形態の投写用ズームレンズはコストを低く抑えられるものとなる。 Since the second lens group G2 and the third lens group G3 are each composed of a single lens, the projection zoom lens according to the present embodiment can keep the cost low.
　以上、＜４群構成の実施形態＞の項の中で説明したことは、第４レンズ群Ｇ４を構成するレンズ枚数の相違を除いて、基本的に、図２～図６の構成に共通して言えるものである。 What has been described above in the section <Embodiment with a four-group configuration> is basically common to the configurations in FIGS. 2 to 6 except for the difference in the number of lenses constituting the fourth lens group G4. It can be said that.
　次に、本発明に係る投写型表示装置の実施形態について、図１３を用いて説明する。図１３は本発明の一実施形態に係る投写型表示装置の一部を概略的に示すものである。この投写型表示装置１００は、光源１０１と、照明光学系１０２と、ライトバルブとしてのＤＭＤ１０３と、本発明の実施形態による投写用ズームレンズ１０４とを備えている。 Next, an embodiment of a projection display device according to the present invention will be described with reference to FIG. FIG. 13 schematically shows a part of a projection display apparatus according to an embodiment of the present invention. The projection display apparatus 100 includes a light source 101, an illumination optical system 102, a DMD 103 as a light valve, and a projection zoom lens 104 according to an embodiment of the present invention.
　この投写型表示装置１００において、光源１０４より射出された光束は、不図示のカラーホイールによって、３原色光（Ｒ、Ｇ、Ｂ）の各光に時系列的に選択変換され、照明光学系１０２によって光束の光軸と垂直な断面における光量分布の均一化が図られてＤＭＤ１０３に照射される。ＤＭＤ１０３においては、入射光の色の切り替わりに応じて、その色光用への変調切替が行われる。ＤＭＤ１０３により変調された光は、投写用ズームレンズ１０４に入射する。そして投写用ズームレンズ１０４は、ＤＭＤ１０３により光変調された光による光学像をスクリーン１０５上に投写する。 In the projection display apparatus 100, the light beam emitted from the light source 104 is selectively converted into each light of the three primary colors (R, G, B) in time series by a color wheel (not shown), and the illumination optical system 102. As a result, the light quantity distribution in the cross section perpendicular to the optical axis of the light beam is made uniform, and the DMD 103 is irradiated. In the DMD 103, modulation switching to the color light is performed according to the color switching of the incident light. The light modulated by the DMD 103 enters the projection zoom lens 104. Then, the projection zoom lens 104 projects an optical image by light modulated by the DMD 103 onto the screen 105.
　なお、本発明の投写型表示装置は図１３に示すものから種々の態様の変更が可能である。例えば、単板のＤＭＤを設ける代わりに、各色光に応じた３枚のＤＭＤによりＲＧＢ各色の変調を同時に行うようにしてもよい。この場合は、投写用ズームレンズ１０４とＤＭＤ１０３との間に色分離／合成プリズム（図示せず）が配置される。また、ＤＭＤ１０３に代えてその他のライトバルブ、例えば透過型液晶表示素子や反射型液晶表示素子等を用いることも可能である。 It should be noted that the projection display device of the present invention can be modified in various ways from that shown in FIG. For example, instead of providing a single plate DMD, RGB colors may be modulated simultaneously by three DMDs corresponding to each color light. In this case, a color separation / synthesis prism (not shown) is disposed between the projection zoom lens 104 and the DMD 103. Further, instead of the DMD 103, other light valves such as a transmissive liquid crystal display element and a reflective liquid crystal display element can be used.
　次に、本発明の投写用ズームレンズの具体的な実施例について説明する。なお先に述べた通り、以下に述べる実施例１および２の投写用ズームレンズは３群構成のものであり、実施例３～６の投写用ズームレンズは４群構成のものである。 Next, specific examples of the projection zoom lens according to the present invention will be described. As described above, the projection zoom lenses of Examples 1 and 2 described below have a three-group configuration, and the projection zoom lenses of Examples 3 to 6 have a four-group configuration.
　＜実施例１＞
　図１に、実施例１の投写用ズームレンズの広角端、望遠端におけるレンズ群の配置を示す。なお、図１についての詳細な説明は前述した通りであるので、ここでは特に必要の無い限り重複した説明は省略する。 <Example 1>
FIG. 1 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens according to the first embodiment. Since the detailed description of FIG. 1 is as described above, the redundant description is omitted here unless otherwise required.
　この実施例１の投写用ズームレンズは、拡大側から順に、負の屈折力を有する第１レンズ群Ｇ１、正の屈折力を有する第２レンズ群Ｇ２および、同じく正の屈折力を有する第３レンズ群Ｇ３を配置して構成されている。 The projection zoom lens of Example 1 includes, in order from the magnification side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens having a positive refractive power. The lens group G3 is arranged.
　第１レンズ群Ｇ１は拡大側から順に、両面が非球面とされた非球面レンズである第１レンズＬ１、両凹レンズである第２レンズＬ２を配置して構成されている。第２レンズ群Ｇ２は拡大側から順に、両凸レンズである第３レンズＬ３、同じく両凸レンズである第４レンズＬ４を配置して構成されている。そして第３レンズ群Ｌ３は拡大側から順に、両凹レンズである第５レンズＬ５、両凸レンズである第６レンズＬ６、負メニスカスレンズである第７レンズＬ７および、両凸レンズである第８レンズＬ８を配置して構成されている。 The first lens group G1 includes a first lens L1 which is an aspherical lens whose both surfaces are aspherical and a second lens L2 which is a biconcave lens in order from the magnification side. The second lens group G2 includes a third lens L3, which is a biconvex lens, and a fourth lens L4, which is also a biconvex lens, in order from the magnification side. The third lens unit L3 includes, in order from the magnification side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a negative meniscus lens, and an eighth lens L8 that is a biconvex lens. It is arranged and configured.
　本実施例において、縮小側の最大像高は０．５５５である。それに対して、最も縮小側に配置された第８レンズＬ８の縮小側のレンズ面における最大有効光束高は、上記最大像高よりも小さい０．４０９である。そこで、十分なレンズバックを確保でき、また、最も縮小側に配された第３レンズ群Ｇ３のレンズ径を小型化することも可能になっている。 In this embodiment, the maximum image height on the reduction side is 0.555. On the other hand, the maximum effective light beam height on the lens surface on the reduction side of the eighth lens L8 arranged on the most reduction side is 0.409, which is smaller than the maximum image height. Therefore, a sufficient lens back can be secured, and the lens diameter of the third lens group G3 arranged on the most reduction side can be reduced.
　表１に、実施例１の投写用ズームレンズの基本レンズデータを示す。ここでは、前述した平行平板ＰＰも含めて示している。表１において、Ｓｉの欄には最も拡大側に有る構成要素の拡大側の面を１番目として縮小側に向かうに従い順次増加するように構成要素に面番号を付したときのｉ番目（ｉ＝１、２、３、…）の面番号を示す。Ｒｉの欄にはｉ番目の面の曲率半径を示し、Ｄｉの欄にはｉ番目の面とｉ＋１番目の面との光軸Ｚ上の面間隔を示している。また、Ｎｄｊの欄には最も拡大側の構成要素を１番目として縮小側に向かうに従い順次増加するｊ番目（ｊ＝１、２、３、…）の構成要素のｄ線（波長５８７．６ｎｍ）に対する屈折率を示し、νｄｊの欄にはｊ番目の構成要素のｄ線に対するアッベ数を示している。 Table 1 shows basic lens data of the projection zoom lens of Example 1. Here, the parallel plate PP described above is also included. In Table 1, in the column of Si, the i-th (i = i = i) when the surface number is given to the component so that the surface on the enlargement side of the component on the most enlargement side is first and increases sequentially toward the reduction side. 1, 2, 3,... The Ri column indicates the radius of curvature of the i-th surface, and the Di column indicates the surface spacing on the optical axis Z between the i-th surface and the i + 1-th surface. Further, in the column of Ndj, the d-line (wavelength 587.6 nm) of the j-th (j = 1, 2, 3,. The νdj column indicates the Abbe number of the j-th component with respect to the d-line.
　なお表１の曲率半径Ｒおよび面間隔Ｄの値は、広角端における投写用ズームレンズの全系の焦点距離を１．００として規格化した値である。また表１中では、所定の桁でまるめた数値を記載している。また曲率半径の符号は、面形状が拡大側に凸の場合を正、縮小側に凸の場合を負としている。 The values of the radius of curvature R and the surface interval D in Table 1 are values normalized by setting the focal length of the entire system of the projection zoom lens at the wide angle end to 1.00. In Table 1, values rounded to a predetermined digit are shown. The sign of the radius of curvature is positive when the surface shape is convex on the enlargement side and negative when the surface shape is convex on the reduction side.
　そして面間隔Ｄのうち、第１レンズ群Ｇ１と第２レンズ群Ｇ２との間隔、第２レンズ群Ｇ２と第３レンズ群Ｇ３との間隔、および第３レンズ群Ｇ３と平行平板ＰＰとの間隔は変倍時に変化する可変間隔であり、これらの間隔に相当する欄にはそれぞれ、「Ｄ」に当該間隔の前側の面番号を付してＤ４、Ｄ８、Ｄ１６と記載している。 Of the surface distance D, the distance between the first lens group G1 and the second lens group G2, the distance between the second lens group G2 and the third lens group G3, and the distance between the third lens group G3 and the parallel plate PP. Are variable intervals that change at the time of zooming. In the columns corresponding to these intervals, D4, D8, and D16 are indicated by adding “D” to the front surface number of the interval.
　以上は、後述する表４、７、１０、１３および１６においても同様である。ただし、４群構成の実施例に関する表７、１０、１３および１６では、変倍時に変化する可変間隔として、第１レンズ群Ｇ１と第２レンズ群Ｇ２との間隔、第２レンズ群Ｇ２と第３レンズ群Ｇ３との間隔、第３レンズ群Ｇ３と第４レンズ群Ｇ４との間隔および、第４レンズ群Ｇ４と平行平板ＰＰとの間隔の４つを示している。そして、上述のような３つあるいは４つの可変レンズ群間隔について、「Ｄ」の後に続く数字は各実施例における構成要素の数に応じて変わっているが、当該間隔の前側の面番号を付して示しているのはどの表でも同じである。 The same applies to Tables 4, 7, 10, 13, and 16 described later. However, in Tables 7, 10, 13, and 16 relating to the examples of the four-group configuration, as the variable interval that changes at the time of zooming, the interval between the first lens group G1 and the second lens group G2, the second lens group G2 and the second 4 shows the distance between the third lens group G3, the distance between the third lens group G3 and the fourth lens group G4, and the distance between the fourth lens group G4 and the parallel plate PP. For the three or four variable lens group intervals as described above, the number following “D” varies depending on the number of components in each embodiment, but the surface number on the front side of the interval is assigned. The same is true for all tables.
　また表２に、実施例１の投写用ズームレンズが変倍する際の広角端、中間焦点位置、望遠端における全系の焦点距離ｆと、上記可変間隔Ｄ４、Ｄ８およびＤ１６の値を示す。これらの数値も、広角端における全系の焦点距離を１．００として規格化した、投写距離が１５１．０８７（同様に規格化した値）の場合の値である。ここに示される通り本実施例では、ズーム比は１．５０倍と高いものとなっている。 Table 2 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end when the projection zoom lens of Example 1 is zoomed, and the values of the variable intervals D4, D8, and D16. These numerical values are also values in the case where the projection distance is 151.087 (the same standardized value) normalized by setting the focal length of the entire system at the wide angle end to 1.00. As shown here, in this embodiment, the zoom ratio is as high as 1.50 times.
　以上述べた表２の記載の仕方は、後述する表５、８、１１、１４および１７においても同様である。ただし、投写距離は実施例毎に固有の値であって、各表の上に示してある。 The manner of description in Table 2 described above is the same in Tables 5, 8, 11, 14, and 17 described later. However, the projection distance is a value unique to each embodiment and is shown on each table.
　また表３に、実施例１の投写用ズームレンズの非球面データを示す。ここでは、非球面の面番号と、その非球面に関する非球面係数を示す。なお非球面係数は、下記の数１に示す非球面式における各係数Ｋ、Ａｉ（ｉ＝３～１６）の値である。また、ここに示す数値において、記号“Ｅ”は、その次に続く数値が１０を底とした“べき指数”であることを示し、その１０を底とした指数関数で表される数値が“Ｅ”の前の数値に乗算されることを示す。例えば、「１．０Ｅ－０２」であれば、「１．０×１０-2」であることを示す。以上述べた表３の記載の仕方は、後述する表６、９、１２、１５および１８においても同様である。またいずれの実施例でも、非球面は第１レンズＬ１の両面のみであるので、面番号Ｓ１およびＳ２に関する非球面係数を示している。
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-M000001
 Table 3 shows aspherical data of the projection zoom lens of Example 1. Here, the surface number of the aspheric surface and the aspheric coefficient related to the aspheric surface are shown. The aspheric coefficient is a value of each coefficient K, Ai (i = 3 to 16) in the aspheric expression shown in the following formula 1. In the numerical values shown here, the symbol “E” indicates that the subsequent numerical value is a “power exponent” with a base of 10, and the numerical value represented by an exponential function with the base 10 is “ Indicates that the value before E ″ is multiplied. For example, “1.0E-02” indicates “1.0 × 10 −2 ”. The manner of description in Table 3 described above is the same in Tables 6, 9, 12, 15 and 18 described later. In any of the embodiments, since the aspheric surface is only on both surfaces of the first lens L1, the aspheric coefficients for the surface numbers S1 and S2 are shown.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-M000001
　ここで図７の（Ａ）～（Ｄ）にそれぞれ、実施例１の投写用ズームレンズの広角端における球面収差、非点収差、ディストーション（歪曲収差）、倍率色収差（倍率の色収差）の各収差図を示す。また同図の（Ｅ）～（Ｈ）にそれぞれ、実施例１の投写用ズームレンズの中間焦点位置における球面収差、非点収差、ディストーション、倍率色収差の各収差図を示す。また同図の（Ｉ）～（Ｌ）にそれぞれ、実施例１の投写用ズームレンズの望遠端における球面収差、非点収差、ディストーション、倍率色収差の各収差図を示す。ここで各収差は、投写距離を前述の１５１．０８７としたときのものである。またこの図７には、実施例１の広角端、中間焦点位置および望遠端におけるＦナンバーＦｎｏ．および全画角２ω（単位は度）を併せて示してある。 Here, FIGS. 7A to 7D respectively show spherical aberration, astigmatism, distortion (distortion aberration), and lateral chromatic aberration (chromatic aberration of magnification) at the wide-angle end of the projection zoom lens of Example 1. The figure is shown. Also, (E) to (H) of the same figure show respective aberration diagrams of spherical aberration, astigmatism, distortion, and lateral chromatic aberration at the intermediate focal position of the projection zoom lens of Example 1. In addition, (I) to (L) in the same figure show aberration diagrams of spherical aberration, astigmatism, distortion, and lateral chromatic aberration at the telephoto end of the projection zoom lens of Example 1, respectively. Here, each aberration is obtained when the projection distance is set to 151.087 described above. FIG. 7 shows the F number Fno. At the wide angle end, the intermediate focal position, and the telephoto end of the first embodiment. The total angle of view 2ω (in degrees) is also shown.
　図７の（Ａ）～（Ｌ）の各収差図は、ｄ線を基準としたものであるが、球面収差図では、Ｆ線（波長波長４８６．１ｎｍ）、Ｃ線（波長６５６．３ｎｍ）に関する収差も示しており、倍率色収差図では、Ｆ線、Ｃ線に関する収差を示している。また、非点収差図ではサジタル方向、タンジェンシャル方向に関する収差をそれぞれ実線、破線で示している。 The aberration diagrams in FIGS. 7A to 7L are based on the d-line, but in the spherical aberration diagram, the F-line (wavelength wavelength 486.1 nm) and the C-line (wavelength 656.3 nm). Are also shown, and the chromatic aberration diagram for magnification shows aberrations for the F-line and C-line. In the astigmatism diagram, aberrations in the sagittal direction and the tangential direction are indicated by a solid line and a broken line, respectively.
　上述した実施例１のレンズ群配置図、表および収差図の記号、意味、記載方法は、特に断りがない限り、以下の実施例２～６のものについても基本的に同様である。また、上述した実施例１のレンズ群配置図（図１）が広角端、望遠端におけるものである点、そして収差図が広角端、中間焦点位置、望遠端におけるものである点も、実施例２～６において同様である。 The symbols, meanings, and description methods of the lens group arrangement diagram, table, and aberration diagram of Example 1 described above are basically the same for the following Examples 2 to 6 unless otherwise specified. In addition, the lens group arrangement diagram (FIG. 1) of Example 1 described above is at the wide-angle end and the telephoto end, and the aberration diagram is at the wide-angle end, the intermediate focal position, and the telephoto end. The same applies to 2-6.
　＜実施例２＞
　図２に、実施例２の投写用ズームレンズの広角端、望遠端におけるレンズ群の配置を示す。この実施例２の投写用ズームレンズは、拡大側から順に、負の屈折力を有する第１レンズ群Ｇ１、正の屈折力を有する第２レンズ群Ｇ２および、同じく正の屈折力を有する第３レンズ群Ｇ３を配置して構成されている。 <Example 2>
FIG. 2 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens according to the second embodiment. The projection zoom lens of Example 2 includes, in order from the magnification side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens having a positive refractive power. The lens group G3 is arranged.
　第１レンズ群Ｇ１は拡大側から順に、両面が非球面とされた非球面レンズである第１レンズＬ１、両凹レンズである第２レンズＬ２を配置して構成されている。第２レンズ群Ｇ２は拡大側から順に、両凸レンズである第３レンズＬ３、同じく両凸レンズである第４レンズＬ４を配置して構成されている。そして第３レンズ群Ｇ３は拡大側から順に、両凹レンズである第５レンズＬ５、両凸レンズである第６レンズＬ６、両凹レンズである第７レンズＬ７、正メニスカスレンズである第８レンズＬ８および、両凸レンズである第９レンズＬ９を配置して構成されている。 The first lens group G1 includes a first lens L1 that is an aspherical lens whose both surfaces are aspherical and a second lens L2 that is a biconcave lens in order from the magnification side. The second lens group G2 includes a third lens L3, which is a biconvex lens, and a fourth lens L4, which is also a biconvex lens, in order from the magnification side. The third lens group G3 includes, in order from the magnification side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a biconcave lens, an eighth lens L8 that is a positive meniscus lens, and A ninth lens L9, which is a biconvex lens, is arranged.
　本実施例において、縮小側の最大像高は０．５５４である。それに対して、最も縮小側に配置された第９レンズＬ９の縮小側のレンズ面における最大有効光束高は、上記最大像高よりも小さい０．４０７である（なおこれらの値も、広角端における全系の焦点距離を１．００として規格化したものである。以下、同様）。そこで、十分なレンズバックを確保でき、また、最も縮小側に配された第３レンズ群Ｇ３のレンズ径を小型化することも可能になっている。 In this embodiment, the maximum image height on the reduction side is 0.554. On the other hand, the maximum effective light beam height on the reduction-side lens surface of the ninth lens L9 arranged on the most reduction side is 0.407, which is smaller than the maximum image height (note that these values are also at the wide-angle end). This is standardized with the focal length of the entire system as 1.00 (hereinafter the same). Therefore, a sufficient lens back can be secured, and the lens diameter of the third lens group G3 arranged on the most reduction side can be reduced.
　表４に、実施例２の投写用ズームレンズの基本レンズデータを示す。また表５に、実施例２の投写用ズームレンズが変倍する際の広角端、中間焦点位置、望遠端における全系の焦点距離ｆと、可変間隔Ｄ４、Ｄ８およびＤ１８の値を示す。ここに示される通り本実施例では、ズーム比は１．５０倍と高いものとなっている。これらの数値は、投写距離が１５１．０７３の場合の値である。また表６に、実施例２の投写用ズームレンズの非球面データを示す。
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
 Table 4 shows basic lens data of the projection zoom lens of Example 2. Table 5 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end, and the values of the variable intervals D4, D8, and D18 when the projection zoom lens of Example 2 is zoomed. As shown here, in this embodiment, the zoom ratio is as high as 1.50 times. These numerical values are values when the projection distance is 151.073. Table 6 shows aspherical data of the projection zoom lens of Example 2.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
　一方図８の（Ａ）～（Ｌ）にそれぞれ、実施例２の投写用ズームレンズの各収差図を示す。ここに示す各収差は、投写距離を前述の１５１．０７３としたときのものである。 On the other hand, FIGS. 8A to 8L show aberration diagrams of the projection zoom lens of Example 2, respectively. Each aberration shown here is obtained when the projection distance is 151.073 described above.
　＜実施例３＞
　図３に、実施例３の投写用ズームレンズの広角端、望遠端におけるレンズ群の配置を示す。この実施例３の投写用ズームレンズは、拡大側から順に、負の屈折力を有する第１レンズ群Ｇ１、正の屈折力を有する第２レンズ群Ｇ２、正の屈折力を有する第３レンズ群Ｇ３および、正の屈折力を有する第４レンズ群Ｇ４を配置して構成されている。 <Example 3>
FIG. 3 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens according to the third embodiment. The projection zoom lens of Example 3 includes, in order from the enlargement side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a positive refractive power. G3 and a fourth lens group G4 having a positive refractive power are arranged.
　第１レンズ群Ｇ１は拡大側から順に、両面が非球面とされた非球面レンズである第１レンズＬ１、両凹レンズである第２レンズＬ２を配置して構成されている。第２レンズ群Ｇ２は、１枚の両凸レンズである第３レンズＬ３から構成されている。第３レンズ群Ｇ３も、１枚の両凸レンズである第４レンズＬ４から構成されている。第４レンズ群Ｇ４は拡大側から順に、両凹レンズである第５レンズＬ５、両凸レンズである第６レンズＬ６、負メニスカスレンズである第７レンズＬ７および、両凸レンズである第８レンズＬ８を配置して構成されている。 The first lens group G1 includes a first lens L1 which is an aspherical lens whose both surfaces are aspherical and a second lens L2 which is a biconcave lens in order from the magnification side. The second lens group G2 includes a third lens L3 that is a single biconvex lens. The third lens group G3 is also composed of a fourth lens L4 which is a single biconvex lens. The fourth lens group G4 includes, in order from the magnification side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a negative meniscus lens, and an eighth lens L8 that is a biconvex lens. Configured.
　本実施例において、縮小側の最大像高は０．５５５である。それに対して、最も縮小側に配置された第８レンズＬ８の縮小側のレンズ面における最大有効光束高は、上記最大像高よりも小さい０．４１４である。そこで、十分なレンズバックを確保でき、また、最も縮小側に配された第４レンズ群Ｇ４のレンズ径を小型化することも可能になっている。 In this embodiment, the maximum image height on the reduction side is 0.555. On the other hand, the maximum effective luminous flux height on the lens surface on the reduction side of the eighth lens L8 arranged on the most reduction side is 0.414, which is smaller than the maximum image height. Therefore, a sufficient lens back can be secured, and the lens diameter of the fourth lens group G4 arranged on the most reduction side can be reduced.
　表７に、実施例３の投写用ズームレンズの基本レンズデータを示す。また表８に、実施例３の投写用ズームレンズが変倍する際の広角端、中間焦点位置、望遠端における全系の焦点距離ｆと、可変間隔Ｄ４、Ｄ６、Ｄ８およびＤ１６の値を示す。ここに示される通り本実施例では、ズーム比は１．５０倍と高いものとなっている。これらの数値は、投写距離が１５１．１２１の場合の値である。また表９に、実施例３の投写用ズームレンズの非球面データを示す。
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000009
 Table 7 shows basic lens data of the projection zoom lens of Example 3. Table 8 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end, and the values of the variable intervals D4, D6, D8, and D16 when the projection zoom lens of Example 3 is zoomed. . As shown here, in this embodiment, the zoom ratio is as high as 1.50 times. These numerical values are values when the projection distance is 151.121. Table 9 shows aspherical data of the projection zoom lens of Example 3.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000009
　一方図９の（Ａ）～（Ｌ）にそれぞれ、実施例３の投写用ズームレンズの各収差図を示す。ここに示す各収差は、投写距離を前述の１５１．１２１としたときのものである。 On the other hand, FIGS. 9A to 9L show aberration diagrams of the projection zoom lens of Example 3, respectively. Each aberration shown here is obtained when the projection distance is 151.121 described above.
　＜実施例４＞
　図４に、実施例４の投写用ズームレンズの広角端、望遠端におけるレンズ群の配置を示す。この実施例４の投写用ズームレンズは、拡大側から順に、負の屈折力を有する第１レンズ群Ｇ１、正の屈折力を有する第２レンズ群Ｇ２、正の屈折力を有する第３レンズ群Ｇ３および、正の屈折力を有する第４レンズ群Ｇ４を配置して構成されている。 <Example 4>
FIG. 4 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens of Example 4. The projection zoom lens of Example 4 includes, in order from the magnification side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a positive refractive power. G3 and a fourth lens group G4 having a positive refractive power are arranged.
　第１レンズ群Ｇ１は拡大側から順に、両面が非球面とされた非球面レンズである第１レンズＬ１、両凹レンズである第２レンズＬ２を配置して構成されている。第２レンズ群Ｇ２は、１枚の両凸レンズである第３レンズＬ３から構成されている。第３レンズ群Ｇ３も、１枚の両凸レンズである第４レンズＬ４から構成されている。第４レンズ群Ｇ４は拡大側から順に、両凹レンズである第５レンズＬ５、両凸レンズである第６レンズＬ６、両凹レンズである第７レンズＬ７、正メニスカスレンズである第８レンズＬ８および、両凸レンズである第９レンズＬ９を配置して構成されている。 The first lens group G1 includes a first lens L1 which is an aspherical lens whose both surfaces are aspherical and a second lens L2 which is a biconcave lens in order from the magnification side. The second lens group G2 includes a third lens L3 that is a single biconvex lens. The third lens group G3 is also composed of a fourth lens L4 which is a single biconvex lens. The fourth lens group G4 includes, in order from the magnifying side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a biconcave lens, an eighth lens L8 that is a positive meniscus lens, and both A ninth lens L9, which is a convex lens, is arranged.
　本実施例において、縮小側の最大像高は０．５５４である。それに対して、最も縮小側に配置された第９レンズＬ９の縮小側のレンズ面における最大有効光束高は、上記最大像高よりも小さい０．４０１である。そこで、十分なレンズバックを確保でき、また、最も縮小側に配された第４レンズ群Ｇ４のレンズ径を小型化することも可能になっている。 In this embodiment, the maximum image height on the reduction side is 0.554. On the other hand, the maximum effective luminous flux height on the lens surface on the reduction side of the ninth lens L9 arranged on the most reduction side is 0.401, which is smaller than the maximum image height. Therefore, a sufficient lens back can be secured, and the lens diameter of the fourth lens group G4 arranged on the most reduction side can be reduced.
　表１０に、実施例４の投写用ズームレンズの基本レンズデータを示す。また表１１に、実施例４の投写用ズームレンズが変倍する際の広角端、中間焦点位置、望遠端における全系の焦点距離ｆと、可変間隔Ｄ４、Ｄ６、Ｄ８およびＤ１８の値を示す。ここに示される通り本実施例では、ズーム比は１．５０倍と高いものとなっている。これらの数値は、投写距離が１５１．０７８の場合の値である。また表１２に、実施例４の投写用ズームレンズの非球面データを示す。
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000012
 Table 10 shows basic lens data of the projection zoom lens of Example 4. Table 11 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end, and the values of the variable intervals D4, D6, D8, and D18 when the zoom lens for projection of Example 4 is zoomed. . As shown here, in this embodiment, the zoom ratio is as high as 1.50 times. These numerical values are values when the projection distance is 151.078. Table 12 shows aspherical data of the projection zoom lens of Example 4.
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000012
　一方図１０の（Ａ）～（Ｌ）にそれぞれ、実施例４の投写用ズームレンズの各収差図を示す。ここに示す各収差は、投写距離を前述の１５１．０７８としたときのものである。 On the other hand, FIGS. 10A to 10L show aberration diagrams of the projection zoom lens of Example 4, respectively. Each aberration shown here is obtained when the projection distance is 151.078 described above.
　＜実施例５＞
　図５に、実施例５の投写用ズームレンズの広角端、望遠端におけるレンズ群の配置を示す。この実施例５の投写用ズームレンズは、拡大側から順に、負の屈折力を有する第１レンズ群Ｇ１、正の屈折力を有する第２レンズ群Ｇ２、正の屈折力を有する第３レンズ群Ｇ３および、正の屈折力を有する第４レンズ群Ｇ４を配置して構成されている。 <Example 5>
FIG. 5 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens according to the fifth embodiment. The projection zoom lens of Example 5 includes, in order from the magnification side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a positive refractive power. G3 and a fourth lens group G4 having a positive refractive power are arranged.
　第１レンズ群Ｇ１は拡大側から順に、両面が非球面とされた非球面レンズである第１レンズＬ１、両凹レンズである第２レンズＬ２を配置して構成されている。第２レンズ群Ｇ２は、１枚の両凸レンズである第３レンズＬ３から構成されている。第３レンズ群Ｇ３も、１枚の両凸レンズである第４レンズＬ４から構成されている。第４レンズ群Ｇ４は拡大側から順に、両凹レンズである第５レンズＬ５、両凸レンズである第６レンズＬ６、両凹レンズである第７レンズＬ７、正メニスカスレンズである第８レンズＬ８、両凸レンズである第９レンズＬ９および、両凸レンズである第１０レンズＬ１０を配置して構成されている。 The first lens group G1 includes a first lens L1 which is an aspherical lens whose both surfaces are aspherical and a second lens L2 which is a biconcave lens in order from the magnification side. The second lens group G2 includes a third lens L3 that is a single biconvex lens. The third lens group G3 is also composed of a fourth lens L4 which is a single biconvex lens. The fourth lens group G4 includes, in order from the magnifying side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a biconcave lens, an eighth lens L8 that is a positive meniscus lens, and a biconvex lens. And a tenth lens L10 which is a biconvex lens.
　本実施例において、縮小側の最大像高は０．５５３である。それに対して、最も縮小側に配置された第１０レンズＬ１０の縮小側のレンズ面における最大有効光束高は、上記最大像高よりも小さい０．４１５である。そこで、十分なレンズバックを確保でき、また、最も縮小側に配された第４レンズ群Ｇ４のレンズ径を小型化することも可能になっている。 In this embodiment, the maximum image height on the reduction side is 0.553. On the other hand, the maximum effective luminous flux height on the lens surface on the reduction side of the tenth lens L10 arranged on the most reduction side is 0.415, which is smaller than the maximum image height. Therefore, a sufficient lens back can be secured, and the lens diameter of the fourth lens group G4 arranged on the most reduction side can be reduced.
　表１３に、実施例５の投写用ズームレンズの基本レンズデータを示す。また表１４に、実施例５の投写用ズームレンズが変倍する際の広角端、中間焦点位置、望遠端における全系の焦点距離ｆと、可変間隔Ｄ４、Ｄ６、Ｄ８およびＤ２０の値を示す。ここに示される通り本実施例では、ズーム比は１．５０倍と高いものとなっている。これらの数値は、投写距離が１２０．５１６の場合の値である。また表１５に、実施例５の投写用ズームレンズの非球面データを示す。
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000015
 Table 13 shows basic lens data of the projection zoom lens of Example 5. Table 14 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end, and the values of the variable intervals D4, D6, D8, and D20 when the zoom lens for projection of Example 5 is zoomed. . As shown here, in this embodiment, the zoom ratio is as high as 1.50 times. These numerical values are values when the projection distance is 120.516. Table 15 shows aspherical data of the projection zoom lens of Example 5.
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000015
　一方図１１の（Ａ）～（Ｌ）にそれぞれ、実施例５の投写用ズームレンズの各収差図を示す。ここに示す各収差は、投写距離を前述の１２０．５１６としたときのものである。 On the other hand, FIGS. 11A to 11L show respective aberration diagrams of the projection zoom lens of Example 5. FIG. Each aberration shown here is obtained when the projection distance is 120.516 described above.
　＜実施例６＞
　図６に、実施例６の投写用ズームレンズの広角端、望遠端におけるレンズ群の配置を示す。この実施例６の投写用ズームレンズは、拡大側から順に、負の屈折力を有する第１レンズ群Ｇ１、正の屈折力を有する第２レンズ群Ｇ２、正の屈折力を有する第３レンズ群Ｇ３および、正の屈折力を有する第４レンズ群Ｇ４を配置して構成されている。 <Example 6>
FIG. 6 shows the arrangement of lens groups at the wide-angle end and the telephoto end of the projection zoom lens according to the sixth embodiment. The projection zoom lens of Example 6 includes, in order from the magnification side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a positive refractive power. G3 and a fourth lens group G4 having a positive refractive power are arranged.
　第１レンズ群Ｇ１は拡大側から順に、両面が非球面とされた非球面レンズである第１レンズＬ１、両凹レンズである第２レンズＬ２を配置して構成されている。第２レンズ群Ｇ２は、１枚の両凸レンズである第３レンズＬ３から構成されている。第３レンズ群Ｇ３も、１枚の両凸レンズである第４レンズＬ４から構成されている。第４レンズ群Ｇ４は拡大側から順に、両凹レンズである第５レンズＬ５、両凸レンズである第６レンズＬ６、両凹レンズである第７レンズＬ７、正メニスカスレンズである第８レンズＬ８、両凸レンズである第９レンズＬ９および、両凸レンズである第１０レンズＬ１０を配置して構成されている。 The first lens group G1 includes a first lens L1 which is an aspherical lens whose both surfaces are aspherical and a second lens L2 which is a biconcave lens in order from the magnification side. The second lens group G2 includes a third lens L3 that is a single biconvex lens. The third lens group G3 is also composed of a fourth lens L4 which is a single biconvex lens. The fourth lens group G4 includes, in order from the magnifying side, a fifth lens L5 that is a biconcave lens, a sixth lens L6 that is a biconvex lens, a seventh lens L7 that is a biconcave lens, an eighth lens L8 that is a positive meniscus lens, and a biconvex lens. And a tenth lens L10 which is a biconvex lens.
　本実施例において、縮小側の最大像高は０．５５３である。それに対して、最も縮小側に配置された第１０レンズＬ１０の縮小側のレンズ面における最大有効光束高は、上記最大像高よりも小さい０．４０８である。そこで、十分なレンズバックを確保でき、また、最も縮小側に配された第４レンズ群Ｇ４のレンズ径を小型化することも可能になっている。 In this embodiment, the maximum image height on the reduction side is 0.553. On the other hand, the maximum effective light beam height on the lens surface on the reduction side of the tenth lens L10 arranged on the most reduction side is 0.408, which is smaller than the maximum image height. Therefore, a sufficient lens back can be secured, and the lens diameter of the fourth lens group G4 arranged on the most reduction side can be reduced.
　表１６に、実施例６の投写用ズームレンズの基本レンズデータを示す。また表１７に、実施例６の投写用ズームレンズが変倍する際の広角端、中間焦点位置、望遠端における全系の焦点距離ｆと、可変間隔Ｄ４、Ｄ６、Ｄ８およびＤ２０の値を示す。ここに示される通り本実施例では、ズーム比は１．６４倍と高いものとなっている。これらの数値は、投写距離が１２０．４７２の場合の値である。また表１８に、実施例６の投写用ズームレンズの非球面データを示す。
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000017
Figure JPOXMLDOC01-appb-T000018
 Table 16 shows basic lens data of the projection zoom lens of Example 6. Table 17 shows the focal length f of the entire system at the wide-angle end, the intermediate focal position, and the telephoto end, and the values of the variable intervals D4, D6, D8, and D20 when the zoom lens for projection of Example 6 is zoomed. . As shown here, in this embodiment, the zoom ratio is as high as 1.64 times. These numerical values are values when the projection distance is 120.472. Table 18 shows aspherical data of the projection zoom lens of Example 6.
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000017
Figure JPOXMLDOC01-appb-T000018
　一方図１２の（Ａ）～（Ｌ）にそれぞれ、実施例６の投写用ズームレンズの各収差図を示す。ここに示す各収差は、投写距離を前述の１２０．４７２としたときのものである。 On the other hand, FIGS. 12A to 12L show aberration diagrams of the projection zoom lens of Example 6. FIG. Each aberration shown here is obtained when the projection distance is 120.472 as described above.
　また表１９に、前記条件式（１）～（３）が規定する条件（つまり文字式の部分）の値を示す。前述した通りここでは、全系の焦点距離ｆwを１．００として示してあるので、fm、frおよびＢｆwの値がすなわち、各々fm／fw、ｆr／ｆwおよびＢｆw ／fwの値となる。
Figure JPOXMLDOC01-appb-T000019
 Table 19 shows values of conditions defined by the conditional expressions (1) to (3) (that is, character expression portions). As described above, since the focal length fw of the entire system is shown as 1.00, the values of fm, fr and Bfw are values of fm / fw, fr / fw and Bfw / fw, respectively.
Figure JPOXMLDOC01-appb-T000019
　以上、実施形態および実施例を挙げて本発明を説明したが、本発明の投写用ズームレンズは、上記実施例のものに限られることなく種々の態様の変更が可能であり、例えば各レンズの曲率半径、面間隔、屈折率、アッベ数を適宜変更することが可能である。 Although the present invention has been described with reference to the embodiments and examples, the projection zoom lens according to the present invention is not limited to the above examples, and various modifications can be made. It is possible to appropriately change the radius of curvature, the surface spacing, the refractive index, and the Abbe number.
　また、本発明の投写型表示装置も前述した構成のものに限られるものではなく、例えば、用いられるライトバルブや、光束分離または光束合成に用いられる光学部材は、既述の構成に限定されず、種々の態様の変更が可能である。 Further, the projection display device of the present invention is not limited to the above-described configuration. For example, the light valve used and the optical member used for light beam separation or light beam synthesis are not limited to the above-described configuration. Various modifications can be made.

Claims (12)

  1. 　移動群として３群ないし４群のレンズ群を移動させて変倍動作を行う投写用ズームレンズにおいて、
    　最も拡大側のレンズ群は負の屈折力を有する移動群から構成され、
    　最も縮小側のレンズ群は正の屈折力を有する移動群から構成され、
    　前記最も拡大側のレンズ群は実質的に２枚のレンズからなり、
    　下記条件式（１）を満たすことを特徴とする投写用ズームレンズ。
    　　－３．５＜ fm／fw ＜－１．０・・・（１）
    ただし、
    　　ｆw：広角端における全系の焦点距離
    　　ｆm：前記最も拡大側のレンズ群の焦点距離     In a projection zoom lens that performs zooming operation by moving the third to fourth lens groups as a moving group,
    The most magnified lens group is composed of a moving group having negative refractive power,
    The most reducing lens group is composed of a moving group having a positive refractive power,
    The most magnified lens group substantially consists of two lenses,
    A projection zoom lens satisfying the following conditional expression (1):
    -3.5 <fm / fw <-1.0 (1)
    However,
    fw: focal length of the entire system at the wide angle end fm: focal length of the lens unit on the most enlarged side
  2. 　前記最も拡大側のレンズ群は実質的に、拡大側より順に、少なくとも１面が非球面である非球面レンズおよび、両凹レンズを配置して構成されていることを特徴とする請求項１記載の投写用ズームレンズ。 2. The lens group according to claim 1, wherein the most magnified lens group includes an aspherical lens having at least one aspherical surface and a biconcave lens in order from the magnification side. Zoom lens for projection.
  3. 　前記非球面レンズはプラスチック材から形成され、前記両凹レンズはガラス材から形成されていることを特徴とする請求項２記載の投写用ズームレンズ。 3. The projection zoom lens according to claim 2, wherein the aspherical lens is made of a plastic material, and the biconcave lens is made of a glass material.
  4. 　下記条件式（２）を満たすことを特徴とする請求項１から３のうちいずれか１項記載の投写用ズームレンズ。
    　　２．０＜ ｆr／ｆw ＜５０．０・・・（２）
    ただし、
    　　fw：広角端における全系の焦点距離
    　　fr：前記最も縮小側のレンズ群の焦点距離     The projection zoom lens according to claim 1, wherein the following conditional expression (2) is satisfied.
    2.0 <fr / fw <50.0 (2)
    However,
    fw: focal length of the entire system at the wide-angle end fr: focal length of the lens unit on the most reduction side
  5. 　前記最も縮小側のレンズ群は拡大側より順に、両凹レンズ、正レンズ、拡大側に凹面を向けた負レンズを有していることを特徴とする請求項１から４のうちいずれか１項記載の投写用ズームレンズ。 5. The lens unit according to claim 1, wherein the lens unit on the most reduction side includes, in order from the magnification side, a biconcave lens, a positive lens, and a negative lens having a concave surface directed toward the magnification side. Projection zoom lens.
  6. 　拡大側より順に実質的に、負の第１レンズ群、正の第２レンズ群および正の第３レンズ群が配列されてなり、
    　変倍に際し前記第１レンズ群、第２レンズ群および第３レンズ群が移動群として各々独立して移動し、
    　広角端から望遠端まで変倍する際に前記第１レンズ群は縮小側に移動し、前記第２レンズ群および前記第３レンズ群は拡大側へ移動することを特徴とする請求項１から５のうちいずれか１項記載の投写用ズームレンズ。     A negative first lens group, a positive second lens group, and a positive third lens group are arranged in order from the magnification side,
    When zooming, the first lens group, the second lens group, and the third lens group move independently as a moving group,
    The first lens group moves to the reduction side and the second lens group and the third lens group move to the enlargement side when zooming from the wide-angle end to the telephoto end. The projection zoom lens according to claim 1.
  7. 　拡大側より順に実質的に、負の第１レンズ群、正の第２レンズ群、正の第３レンズ群および正の第４レンズ群が配列されてなり、
    　変倍に際し前記第１レンズ群、第２レンズ群、第３レンズ群および第４レンズ群が移動群として各々独立して移動し、
    　広角端から望遠端まで変倍する際に前記第１レンズ群は縮小側に移動し、前記第２レンズ群、前記第３レンズ群および前記第４レンズ群は拡大側へ移動することを特徴とする特徴とする請求項１から５のうちいずれか１項記載の投写用ズームレンズ。     A negative first lens group, a positive second lens group, a positive third lens group, and a positive fourth lens group are arranged in sequence from the magnification side,
    When zooming, the first lens group, the second lens group, the third lens group, and the fourth lens group move independently as a moving group,
    When zooming from the wide-angle end to the telephoto end, the first lens group moves to the reduction side, and the second lens group, the third lens group, and the fourth lens group move to the enlargement side. The projection zoom lens according to claim 1, wherein the zoom lens for projection is provided.
  8. 　前記第２レンズ群は１枚の単レンズで構成されていることを特徴とする請求項７記載の投写用ズームレンズ。 8. The projection zoom lens according to claim 7, wherein the second lens group comprises a single lens.
  9. 　前記第３レンズ群は１枚の単レンズで構成されていることを特徴とする請求項７または８記載の投写用ズームレンズ。 The projection zoom lens according to claim 7 or 8, wherein the third lens group is composed of a single lens.
  10. 　下記条件式（３）を満たすことを特徴とする請求項１から９のうちいずれか１項記載の投写用ズームレンズ。
    　　１．０＜Ｂｆw ／fw 　・・・（３）
    ただし、
    　　fw：広角端における全系の焦点距離
    　　Ｂｆw ：広角端における全系のバックフォーカス（空気換算距離）     The projection zoom lens according to claim 1, wherein the following conditional expression (3) is satisfied.
    1.0 <Bfw / fw (3)
    However,
    fw: Focal length of the entire system at the wide angle end Bfw: Back focus of the entire system at the wide angle end (air equivalent distance)
  11. 　最も縮小側のレンズ面における最大有効光束高が、縮小側の最大像高より小さいことを特徴とする請求項１から１０のうちいずれか１項記載の投写用ズームレンズ。 11. The projection zoom lens according to claim 1, wherein the maximum effective light flux height on the lens surface closest to the reduction side is smaller than the maximum image height on the reduction side.
  12. 　光源と、ライトバルブと、前記光源からの光束を前記ライトバルブへ導く照明光学部と、請求項１から１１のうちいずれか１項記載の投写用ズームレンズとを備え、前記光源からの光束を前記ライトバルブで光変調し、前記投写用ズームレンズによりスクリーンに投写する構成を有することを特徴とする投写型表示装置。 A light source, a light valve, an illumination optical unit that guides a light beam from the light source to the light valve, and a projection zoom lens according to any one of claims 1 to 11, wherein the light beam from the light source A projection display device, characterized by having a configuration in which light modulation is performed by the light valve and projection onto a screen is performed by the projection zoom lens.
PCT/JP2013/002173 2012-04-02 2013-03-29 Zoom lens for projection, and projection-type display device WO2013150757A1 (en)

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